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Maarten Baert

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  1. Informative
    Maarten Baert got a reaction from KnightSirius in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  2. Like
    Maarten Baert got a reaction from Zulg in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  3. Agree
    Maarten Baert got a reaction from sotiris.bos in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  4. Informative
    Maarten Baert got a reaction from NinJake in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  5. Like
    Maarten Baert got a reaction from -TesseracT- in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  6. Like
    Maarten Baert got a reaction from MVPernula in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  7. Like
    Maarten Baert got a reaction from Prof7 in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  8. Like
    Maarten Baert got a reaction from Glenwing in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  9. Like
    Maarten Baert got a reaction from Brainstew in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  10. Like
    Maarten Baert got a reaction from Geekazoid in The flawed math behind curved monitors   
    Thanks . It took a few hours. The models are pretty simple and you can do things pretty fast in Blender once you're used to it.
  11. Like
    Maarten Baert got a reaction from Geekazoid in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  12. Like
    Maarten Baert got a reaction from LarsReviews in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  13. Like
    Maarten Baert got a reaction from Oshino Shinobu in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  14. Like
    Maarten Baert got a reaction from Levent in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  15. Like
    Maarten Baert got a reaction from Deddie in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  16. Like
    Maarten Baert got a reaction from withtheeye in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  17. Like
    Maarten Baert got a reaction from mansoor_ in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  18. Like
    Maarten Baert got a reaction from dizmo in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  19. Like
    Maarten Baert got a reaction from Unhelpful in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
  20. Like
    Maarten Baert got a reaction from AlwaysFSX in The flawed math behind curved monitors   
    Opinions on curved monitors vary a lot: some people claim it's the greatest thing ever, others say it's just a fad. But so far I haven't seen anyone who actually tried to verify the main claim of curved monitors. Manufacturers claim that the curvature ensures that all pixels on the screen are the more or less the same distance away from your eyes, which supposedly avoids the distortion often seen close to the edges of screens. This claim is wrong. If you do the math, you will find that a curved screen actually makes the distortion worse.
    The short explanation is that virtually all cameras have flat image sensors. These sensors do indeed distort the image - objects close to the edges will appear stretched. The thing is, the distortion caused by the flat sensor is canceled out exactly by the distortion of the flat screen. It really doesn't matter that the pixels near the edges of the screen are further away from your eyes, as long as the screen has the same shape as the camera sensor (and the same field of view). If you want a more complete explanation, and some actual proof, read on.
    The test image

    I made a simple test image in Blender. It's a simple rendering of a grid of spheres. Each of the spheres is perfectly round, but you can clearly see that the spheres close to the edges appear stretched. I'm intentionally using a very wide field of view (roughly 90 degrees) to make the effect more obvious. You can download the original source files at the end of this post.
    Flat monitor
    Let's see what happens when the test image is displayed on an ordinary flat monitor. This is a model of a basic 16:9 monitor (64cm x 36cm, roughly 29"):

    This is what it would look like when you're sitting directly in front of it:

    The spheres near the center look fine, but those closer to the edges are stretched. But watch what happens when you rotate the camera towards one of the corners:

    Somehow, the spheres in the corner now look normal whereas the spheres in the center are stretched! No, I didn't mess with that image, there's no Photoshopping/compositing/whatever going on here. All I did was rotate the camera. How is this possible? Simple: when the camera faces the corner of the screen instead of the center, the screen tilted relative to the camera. This tilt compensates the distortion that we saw earlier.
    Does this also work in real life? Of course! You just have to sit in the right spot, so your field of view matches that of the camera. Since I used a very wide field of view for the test image (90 degrees), you need to sit very close to see it properly. For example, if your screen is 50cm wide, your eyes should be 25cm away from the screen to watch the test image. Ideally your eyes should be in the center, but you obviously can't have both of your eyes in the center at the same time. In order to get a perfect result, you should close one eye and make sure that your other eye right in the center of the screen. Now open the test image in your browser, make it fullscreen (press F11 - this is important), and watch. You shouldn't be able to see any distortion at all, no matter where you look.
    Curved monitor
    Now let's try this again with a curved monitor. I couldn't find any actual specs regarding the amount of curvature used by real monitors, so I just used a screenshot of Linus' LG 34U97 unboxing video to get some numbers. The 34U97 is 83cm wide, and based on the unboxing video, it looks like the center is recessed about 2.5cm compared to the corners (which is far less than the photos on the product page suggest - typical marketing I guess). This corresponds to the curvature of a circle with a 7m diameter, which means the 'sweet spot' is located 3.5m away from the center of the screen (makes sense for a TV, but rather strange for a computer monitor IMO). Anyway, I took the model that I used earlier and gave it the same curvature as the 34U97, and this is the result:

    You can clearly see the curvature when you're sitting right in front of it, but does it actually make the image better? Not at all. The edges are closer to you, which means the spheres near the edges appear even larger than they were already! Now let's rotate the camera again:

    It's still more or less okay, but it's not as 'perfect' as with the ordinary flat monitor.
    Highly curved monitor
    Let's try this again with a monitor with a higher curvature, just to see what will happen. The 'sweet spot' for this monitor is just 1m away from the center (instead of 3.5m).

    It just gets worse. Here's a comparison of the three cases. I've overlaid a green circle on top of the spheres to show you the distortion:

    In the case of the flat monitor, the distortion is canceled out almost perfectly, resulting in a near-perfect circle. In the other two cases, not so much.
    So why do movie theaters use curved screens?
    Because the projectors used in movie theaters contain lenses, which adds lens distortion. The screen is curved to cancel out the lens distortion. Monitors do not use lenses, so there's no reason to make them curved.
    Don't cameras have lenses too?
    There are many different types of camera lenses and they all have a unique distortion pattern. To make things even worse, the distortion pattern depends on zoom and focus as well. There's no way you can compensate all those different distortion patterns just by using a slightly curved screen. Only the camera crew can properly correct lens distortion, since only they know what lenses were used to capture the footage.
    What about improved viewing angles?
    As far as I can tell, this claim is actually correct. For example, the edges of the 34U97 are tilted about 7 degrees compared to a flat monitor. This should effectively increase the maximum viewing angle by 7 degrees. So if you're willing to accept a small amount of distortion to get a better maximum viewing angle, a curved monitor makes sense. There's some good news though: as Linus correctly pointed out, the curvature has little effect when you are sitting further away from the screen. And you get the best possible viewing angle when you're sitting in the 'sweet spot', which is 3.5m away from the screen. So a curved screen could actually make sense for a TV, but not for a computer monitor. Of course the distortion increases once you move away from the center, but you still get most of the benefit of the improved viewing angle.
    What do you think? Would you still buy a curved monitor to improve the maximum viewing angle, even if the image becomes slightly distorted?
    Source files (Blender)
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