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From: ImageAnalyst <imageanalyst@mailinator.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: machine vision-Color Matching
Date: Thu, 28 Feb 2008 20:30:56 -0800 (PST)
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On Feb 28, 7:18=A0am, "John D'Errico" <woodch...@rochester.rr.com>
wrote:
> "Vihang Patil" <vihang_pa...@yahoo.com> wrote in message
>
> <fq632c$i7...@fred.mathworks.com>...
>
> > Thanks John and ImageAnalyst, will definately work on your
> > suggestions.
> > Its quite true what John said, about human perception of
> > color. I too had a similar experience once, when me and my
> > brother were lazing on the bed and I told him the celing
> > is looking pale yellow. While he was pretty sure that it
> > was pure white. We had a good long debate, where finally I
> > won "Since I am the elder one". That normally happens, I
> > guess the elders bullies the younger and make them accept
> > that they were wrong.
> > But Jokes apart I think I will need to do extensive study
> > on color recognition.
> > Thanks and Regards
> > Vihang
>
> About 20 years ago I did some studies on color
> blindness. This brought me in contact with a
> color blind opthamologist, as well as a few other
> people who were color blind.
>
> The doctor had an interesting story to tell - he
> never knew he was color blind until med school,
> where he had a class where they showed the
> Ishihara plates and he saw the wrong things!
> The point is that many people who have this
> characteristic don't actually know they have it,
> or it takes them years to realize. A person might
> also have various degrees of color anomaly.
>
> http://mysite.du.edu/~jcalvert/optics/colvisn.htm
>
> Finally, I was also reading recently that some
> women even have 4 distinct types of cones in
> their eyes. They see color in 4 dimensions. Do
> a Google search for the word "quadchromatic"
> or "tetrachromatic women".
>
> John

Most birds and fish also have 4 cones so their color vision is more
accurate than humans.  Makes sense when you think about it because
birds and fish are among the most brilliantly colored animals.  Dogs
have two types of cones so can still see color (http://ask.yahoo.com/
20020902.html) contrary to what many people think.  I've never heard
of people with 4 types of cones but I guess it could happen.  Some guy
once wrote a book about an island in the Pacific where a good portion
of the people only had 1 type of cone and so they saw in monochrome.