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Re: color value interpolation from colorbar [message #64127 is a reply to message #64125]

Thu, 04 December 2008 09:38

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

j.coenia@gmail.com writes:

> I have a color-coded medical image.
>
> There is a colorbar on the image, for example a red-to-yellow gradient
> valued from 1 to 100.
>
> There is *not* a one-to-one correspondence between the colors in the
> colorbar and the colors in the image. There are many more
> intermediate reds, oranges, and yellows in the image than in the
> colorbar.
>
> What is the correct way to interpolate gradient values to all the
> unknown image colors from the discrete colors/gradients defined in the
> colorbar?

First of all, if there are colors in the image that are not
in the colorbar, then the color bar is fairly useless to you.
My guess is that this has been coded incorrectly. (There can
be colors in the colorbar that are not in the image, of course,
but not the other way around.)

I *suppose* a color bar could be drawn with discrete colors from
the image, so that the user could be encouraged to interpolate
values between colors, but this would be a lousy way to run a
railroad and the programmer should probably have his IEPA card
revoked.

> (The documentation for INTERPOL and INTERPOLATE has not helped me so
> far.)

No, I can imagine not. :-)

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Re: color value interpolation from colorbar By: j.coenia@gmail.com on Thu, 04 December 2008 13:23
		Re: color value interpolation from colorbar By: j.coenia@gmail.com on Thu, 04 December 2008 13:06
		Re: color value interpolation from colorbar By: Vince Hradil on Thu, 04 December 2008 12:11
		Re: color value interpolation from colorbar By: David Fanning on Thu, 04 December 2008 11:50
		Re: color value interpolation from colorbar By: j.coenia@gmail.com on Thu, 04 December 2008 11:15
		Re: color value interpolation from colorbar By: David Fanning on Thu, 04 December 2008 09:38
		Re: color value interpolation from colorbar By: pgrigis on Thu, 04 December 2008 13:35
		Re: color value interpolation from colorbar By: Vince Hradil on Thu, 04 December 2008 13:31

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