P3D Re: "Too much depth"

[Chris Jones <c.jones@xxxxxxxxx>]

At 21:17 04/11/99 -0700, Gabriel wrote:
>If your trying to say that the 
>"stereostereopsis" process differs, depending on the
>distance, please say so! :-)

That's what I've been trying to say! :)

Well it's what I've read in the literature anyway. I wouldn't bet my life
on it, but at least it made it past peer review.

>Gabriel
>>>That's interesting but I haven't seen any examples or
>>>proof of this yet (that it is a different process).
>>>Wouldn't it still be retinal disparity at play here?
>
>Chris,
>>It's always retinal disparity in stereopsis. The original
>>1971 reference for this is in the post just previous to this
>>one, by Bishop & Henry.
>
>Yes, I know. This was a rhetorical question. :-)

Sorry, poor phrasing. The reference was to an example of a paper on
different types of stereopsis at different distances.

>Chris,
>>With one eye you couldn't resolve the motion in 3 dimensions -
>>the change in size of an object as it moves toward you isn't
>>precise enough (I think) or dynamic enough to be used for depth
>>motion perception. It's much more accurate to use two eyes.
>
>I agree, BUT I was referring to motion in the commonly understood
>y axis (motion parallax). This is a monocular depth cue! This cue
>is (if I remember correctly) right behind stereopsis for being a
>very strong depth cue.

By the y-axis you mean up and down in real life?

>Chris goes on to write,
>>Studies show a big difference in the range over which stereopsis
>>operates between the static and dynamic cases. Dynamic stereopsis
>>uses a wider disparity range (presumably for objects whizzing
>>close to the head!), a shorter latency and better use of areas
>>of the retina away from the fovea. There are also chrominance and
>>luminance differences.
>
>That's interesting but HOW did they isolate the known strong
>monocular depth cue of motion parallax in their assessment!?! Is
>there are third unique depth cue when viewing stereo motion
>parallax? ;-)

Maybe so - I'm afraid I got lost in the neurobiology of the article! But
the references are there should you want to check them out.

If and when I find the answer I'll be sure to let you know :)

-- 

Chris Jones 
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