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Re: color_quan & gif files [message #16562 is a reply to message #16489]

Fri, 30 July 1999 00:00

Liam Gumley
Messages: 473
Registered: November 1994

Senior Member

David Fanning wrote:
> A further advantage of the CUBE method is that the colors it
> produces are independent of the input image. Thus, it is likely
> to work better with primary colors of the sort used in plots.
> Rather than, say, the colors used in images.

Indeed, it depends on your application. If you are working with plots,
David's suggestion no doubt produces better results. However for my
applications (images), the statistical method seems to work better. I've
created a couple of test images if anyone is interested. If they seem
dark, you may wish to view them in an application which allows gamma
correction.

ftp://origin.ssec.wisc.edu/pub/gumley/test1.gif
was created with
image = color_quan(image, 1, r, g, b, colors=256)

ftp://origin.ssec.wisc.edu/pub/gumley/test2.gif
was created with
image = color_quan(image, 1, r, g, b, cube=6)
Note the speckle on the cloud feature to the right of the white box. The
speckle is more apparent when gamma is adjusted to give a pleasing image
brightness.

Cheers,
Liam.

--
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley

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[Message index]

		color_quan & gif files By: Simon Hall on Thu, 29 July 1999 00:00
		Re: color_quan & gif files By: davidf on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Liam Gumley on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: davidf on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Liam Gumley on Fri, 30 July 1999 00:00
		Re: color_quan & gif files By: Simon Hall on Fri, 30 July 1999 00:00

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