Re: Profiling Digital Cameras
Re: Profiling Digital Cameras
- Subject: Re: Profiling Digital Cameras
- From: drdot <email@hidden>
- Date: Sat, 09 Mar 2002 09:34:50 -0800
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What do you do in a "mixed" lighting situation -- fluorescent, daylight and
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tungsten sources in the filed of view?
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Roger Breton
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You could profile them the same. The problem presents itself when the light sources are
coming from different angles. This produces different lighting situations on different
sides of the illuminated 3d object. You can only profile for one of the lit sides by
facing your color target toward one of the lighting sources. This effectively profiles
part of the image. This problem is common in basic photography and has always been a
problem for us when scanning car show photographs and badly lit "Garage" shots of cars.
In these cases you just do the best you can and color correct the images to be
acceptable. Typically the fluorescent-lit areas are green. So we can attack the green
colors by adjusting luminance and saturation of the green colors. Of course accuracy goes
out the window. Some things just cant be controlled like our brain can with our vision.
I think the main issue of "Profiling" a digital camera is a relativity issue. Profiling a
scanner can allow a match to that photograph. But the photograph seldom represents the
real object that was photographed perfectly in the first place. It is really easy to
compare a photograph to a printed representation of that photograph. But it is another
issue to compare a printed representation of a scene to the actual scene.
Sam Landry
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