Path: utzoo!attcan!uunet!shakti!dilip
From: dilip@ncst.ernet.in (Dilip Khandekar)
Newsgroups: comp.graphics.visualization
Subject: Distortion of a sphere in raytracing.
Keywords: raytracing, distortions, perspective-projection.
Message-ID: <1098@shakti.ncst.ernet.in>
Date: 19 Nov 90 08:41:05 GMT
Reply-To: dilip@ncst.ernet.in (Dilip Khandekar)
Organization: National Centre for Software Technology, Bombay, INDIA
Lines: 19


If the pin-hole camera model is used for projection in raytracing and the 
scene contains a sphere in an extreme corner, the sphere looks like an 
ellipsoid. It can be shown that this is because of the projection-plane when
it intersectes a cone (defined by the rays to every point in the sphere from
the center of projection) the resulting curve of intersection is an ellipse.

   I encountered the problem and would be interested in any method
or projection-model which circumvents this problem. If the pin-hole camera
model is not a good model for the human eye-brain system then is there any
other model which is more accurate?

- dilip
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Dilip Khandekar
Graphics and CAD Divn.,                 email:   dilip@ncst.ernet.in
National Centre for Software Tech.,           or uunet!shakti!dilip
Juhu,   Bombay,   INDIA.                  Tel: +91-022-6201606,6201574.
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