[photo-3d] Re: Chromostereopsis

["Gabriel Jacob" <gjacob@xxxxxxxxxxx>]

Jim Norman writes:
>But what's interesting to me about Shab's example No. 6 (the stereo pair
>of the red and blue lines) is the following: (1) when I look at the
>lines without merging the two images into a stereo pair, just with my
>unaided eyes, the outer blue lines clearly stand out in front of the
>inner red lines, 

It kind of funny because yesterday night I was working on creating
some examples similar to Shab's nice illustration 6, but with some
slight modifications. I hadn't seen his web page till today. It was
getting late so I haven't finished it yet. Hopefully I'll get time to
post them up this evening. 

>and (2) when I free view the pair to merge them into a stereo pair,
>the apparent depth difference between the blue and red lines
>disappears. Does anyone else have this experience, or is it just me?

Very good observations Jim! The example I was attempting demonstrates
exactly what you observed (and even more pronounced)! My purpose was
to demonstrate how chromatic aberrations are detrimental to the 
stereo effect in stereo pairs, be it slides, prints, B&W or color
(phew!). Clearly, you have seen this!

Note, I do although have to mention that with unaided eyes and without
merging the two images, I see the red in front of the blue.

A few days ago it was mentioned how chromatic aberrations are not 
seen with the unaided eye. I noted how we supposedly do see chromatic
aberrations but the brain learns to tune it out. It occurred to me
soon after that the stereo sis we see with red objects appearing
nearer than blue objects (or is it the other way around?) is an
example chromatic aberrations in the eye, albeit a severe one. 

P.S. One of course one shouldn't confuse the stereopsis we see due
to chromatic aberrations, viewing red/blue objects, as enhancing
the effect in stereo-pairs! Quite the contrary. 

Gabriel