T3D Re: acuity enhanced with binocular vision

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Wed, 18 Mar 1998 01:13:20 -0700
>From: Peter Abrahams <telscope@xxxxxxxxxx>
>Subject: T3D acuity enhanced with binocular vision

>In times past, this list has discussed the enhancement of vision when both
>eyes are used, as compared to monocular vision.  (Enhanced in addition to
>the potential for stereoscopy).  I had read conflicting reports on whether
>acuity was improved with binocular vision.  I recently found a seemingly
>authoritative article on the subject.

>Binocular Enhancement of Visual Acuity.  Ron Cagenello, Aries Arditi, & D.
>Lynn Halpern.  Journal of the Optical Society of America A, vol. 10, #8,
>1993, pp1841-1848.  Using both eyes as compared to one, perception of
>contrast increases by 40 to 50 percent...

Thanks for bringing this to our attention - I thought it was very
interesting.

>The published test measured acuity, using block letters on a computer
>monitor and a Stereographics stereo display program...

It seems a little strange that they would use a sequential frame LCS stereo
display as the source, as this introduces possible issues of phosphor decay
rates/flicker, time disparity between peak brightness of left and right
images, differences in electrical performance of glasses or monitor depending
on what's shown, spatial separation of red, green, and blue pixels,
reflections, and the extreme difficulty of *accurately* measuring contrast 
ratio on small features on a CRT. In other words, to the original issue of
human visual perception, they've added a number of display issues and
issues relevant to the human perception of CRT displays in particular.
Visual perception and display characterization are both large, complex
fields, which makes it doubly difficult to acquire sufficient expertise
in both fields. Did the paper discuss any methods used to allow for
display-related issues?

Note: There's no doubt that a test of this kind can measure with complete
accuracy the visual response to a Stereographics display system. The question
is how closely that will correlate to visual response for other display
systems, paper cards, real-world situations, etc.

I do not know the authors, and certainly would not want to question their
ability, and I have not seen the article. I'm only asking on theoretical
grounds, based on items I've seen concerning display characteristics.

John R


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