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Newsgroups: comp.soft-sys.matlab
Subject: Re: machine vision-Color Matching
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From: fburton@nyx.net (Francis Burton)
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In article <e7d1eb41-4679-4640-a3b7-c341c2cdd5d5@e23g2000prf.googlegroups.com>,
ImageAnalyst  <imageanalyst@mailinator.com> wrote:
>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/

Ah, that explains why dogs' coats are so drab. ;-)

>20020902.html) contrary to what many people think.

Some horsey people used to think that equines are totally colour
blind. In fact, they are also dichromats (two cone types) along
with a lot of other mammals.

>  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.

That would be Oliver Sacks:
http://www.oliversacks.com/island.htm

Francis