SvennoJ said:
WereKitten said:
SvennoJ said:
Studies have shown people can still tell a difference upto 100 cycles per degree, or 200 pixels per degree.
So a 52" diagonal screen at 80 inches insn't 'retina' until you have 6491 x 3651 pixels. That's when anti aliasing becomes irrelevant.
At 30 cycles per degree you start to lose the ability to see the pixels themselves, but you will still see aliasing occuring.
...
|
Thanks for the quantitative info. I referred in my post to "Steve Jobs' magic number" because Zappykins started from 300 DPI, so I thought that's where he was starting for his calculations, but I'm no optometrist :)
I have read from multiple sources that a 20/20 sight maps to a minute of arc due to the way the Snellen charts are built. For example the 20/20 samples are built on 5x5 grids of 5 minutes of arc total width, thus they can contain 5 "pixels" or 2.5 cycles per main direction.
Your numbers point to 3x as much, but are they for statistical outliers - i.e. exceptional sight - or for the "normal" vision?
|
That 100 cpd is based on tests NHK has done by showing people 2 images side by side at different cpd and asking which one looks / feels more real. They determined 100 cpd as an upper limit. http://www2.tech.purdue.edu/Cgt/courses/cgt512/discussion/Chastain_Human%20Factors%20in%20UDTV.pdf
20/20 vision is the limit at which you can determine detail, or read text. You will not be able to read pixel font text at 100 cpd. Yet you can still tell a difference, which probably also has to do with the grid pattern of display pixels.
Btw how can we tell when anti-aliasing is perfect? I see aliasing effects too in real-life. For example when you walk towards a baseball field from a distance with 2 chain link fences overlapping at opposite sides of the field, you see all kinds of moire patterns and stairstepping patterns going on. Editting all that out doesn't represent reality truthfully.
|
The lattest,though, is not a sampling artifact. It's down to earth physical interference... We will need ray-tracing for that, before we worry about removing it. Nice use of GPU resources.
