Originally Posted by B 26354
What I don't understand, is what part of high-school Plane Geometry didn't get across to the curved-screen designers, when they failed to consider the amount of additional distortion that a curved screen would introduce to off-center viewers.
Here is what one person with a PHD in physics wrote:
The slight curvature reduces visual geometric distortion: When you watch a perfectly flat TV screen, the corners of the screen are further away than the center so they appear smaller. As a result, the eye doesn’t see the screen as a perfect rectangle – it actually sees dual elongated trapezoids, which is keystone geometric distortion. The slight curvature on the LG OLED TV reduces this subtle keystone geometric distortion by 50 percent at a typical 8 foot (2.4 meter) viewing distance.
The slight curvature improves viewing from the sides away from the central sweet spot: A second and more subtle point: people sitting off to the sides away from the central sweet spot actually get a somewhat better viewing experience than with a flat screen because the curved screen accommodates their viewing direction better by compensating for some of the uneven image foreshortening that is seen with a flat screen: the image on the side of the screen closest to you appears larger, and the image on the side of the screen furthest away appears smaller. The inward curvature of the screen compresses the foreshortening of the image on the near side that appears larger, and the curvature on the far side enlarges the distant part of image that appears smaller, which improves the overall screen image geometry that is seen away from the central sweet spot.
I've thought about writing to him as I don't get some of that. For one, since the screen isn't curved vertically, for a viewer on the right side the right edge of the screen is too close to them already with a flat screen and the curve brings it even closer, so seems like more distortion than for flat for the height of the image on the same side the viewer is sitting.
It's obvious that one person, sitting at the focal-point of the screen's curvature, will benefit from having the picture's distortion reduced to zero.
It isn't obvious to me. Maybe you or someone else can explain it.
I assume you are talking about the geometric distortion.
If a person stands in the center of a soccer field and looks at one of the rectangular goals then the sides will be physically further away from them than the center. The human visual system takes this into account. If the sides are the same distance away and the same height as the center then the goal isn't a flat rectangle, it is curved.
It seems to me that the claim that the sides need to be brought closer because otherwise a rectangle doesn't look right is like claiming that if I look at a rectangular wall it won't look like a rectangle. Of course it isn't a rectangle on the back of my eye, but we learn over many years what a rectangle in real life is supposed to look like.
Is the claim that if somebody took a picture of a soccer goal from the middle of the field and displayed it on a flat panel that the geometry would look wrong compared to the geometry that would have been seen in real life?