[QUOTE=Emmanuel BIGLER;1242851If you include the human vision in 'imaging systems', then tell me what the relevant linear correspondence between input and output and we can continue the conversation [/QUOTE]
For the purposes of perceived sharpness and detail, it's really not as complicated as you're making it out to be. The basics are pretty basic. And with some clever homegrown photoshop experiments you can demonstrate them to yourself and to anyone.
Our visual cortex determines sharpness and "image quality" almost exclusively with contrast in the range of 1 lp/mm to 5 lp/mm. Anything higher frequency than that range is essentially inconsequential. And anything lower frequency than that range is practically irrelevant, since any visual system that does an adequate job at the high frequencies will do a more-than-adequate job at the low ones.
There are now piles of research showing this. And I've demonstrated it by incorporating these lessons into sharpening routines. I've shown many people inkjet prints that look more like contact prints to them than actual contact prints from the same negative.
I agree with everything you're saying about audio. Human psychoacoustics seems like a much less mature and much more mysterious field than human vision.
Although one caveat: I don't get your point with the beat notes of the organ pipes. That's a very simple, completely linear phenomenon. If you add two sine waves that are slightly off from each other, you'll see aliasing in the form of a non-signal, low frequency wave. Both it and visual moiré patterns are simple, easily calculable phenomena.
The examples of visual and auditory illusions play more to neurophysiological quirks, and both more interesting and less easily quantifiable with simple physics.
Bookmarks