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From: kruppd@westminster.ac.uk (Declan Kruppa)
Subject: Re: Differences between successively grabbed images
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Date: Fri, 23 Jun 1995 15:27:38 GMT
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: -I have a couple of ideas as to what is causing the changes, but
: [...]
: -Suspicion #1: Since the lights are AC, the fluctuations in the
: -        voltage produces a similar change in the lamp output.
: -        The image being digitized is then be grabbed at 
: -        different intervals of the power cycle which results in
: -        the different RGB values for an identical scene.

: Very possible, depending on exposure time of camera.
: See lights suggestion above

i thought that tungsten lamps were too slow to follow the ac
fluctuations of their pwr source since the temperature of the 
filament did not have time to change. A flourescent lamps output
is able to reproduce the ac character of the supply

