Perception of Gloss and Matt reflection

Hawley K. Rising III rising at a.crl.com
Thu Feb 22 07:10:26 EST 1996


In message <233387536wnr at oimsdnp.demon.co.uk> - Peter Robinson <Peter at oimsdnp.d
emon.co.uk> writes:
>In article: <824752552.8119 at dorrell.demon.co.uk>  p at dorrell.demon.co.uk (Philip 
>Dorrell) writes:
>> 
>> If an object reflects light by Matt reflection, then the colour and intensity 
>> of light coming from a given point on the surface of the object is roughly 
>> independent of the direction it is being seen from.
>> 
>> If it reflects light by Gloss reflection, then it depends both on the 
>> direction it is being seen from and on the position of the light source.
>> 
>> Humans can certainly perceive the 3-D shapes of objects whichever of these
>> two sorts of reflection is involved. But I imagine that the processing
>> involved must be different in each case, and may even involve distinct areas
>> of the brain (presumably in the visual cortex). 
>
>Pardon???
>
>Seeing in 3D is solely dependant on the position of the eyes (two minimum) 
>relative to the subject and each other. It's true that with a glossy surface and 
>directional lighting that the two eyes may see a slightly different image, but this 
>doesn't effect how you see 3D. In fact, the eyes need a different image to form the 
>3D image. If you have a large plain matt surface with even lighting, then you might 
>lose the 3D capability all together because there is no difference in the image 
>received by each eye.
>
>I think you've got a basic misunderstanding of the princples of 3D.
>
>-- 
>Peter
>
>Peter at oimsdnp.demon.co.uk
>Peter.Robinson at oxinst.co.uk

Peter -- I believe it is you who have a basic misunderstanding here.  I would 
call your attention to a phenomenon called VISIDEC, in which 3D images are 
created on a 2D CRT display by taking *vertically* binocular material and 
presenting it in an oscillating manner in time, a demonstration that the 
brain generates 3D in the vertical direction by temporal 
comparison, not spatial comparison as in horizontal binocularity.  
The reason I bring it up is because it does *not* rely on two eyes, and it
*is* 3D, even by your definitions.

Hawley Rising
rising at a.crl.com







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