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Re: problem with writing a 2D image .tiff [message #53796 is a reply to message #53502]

Thu, 03 May 2007 10:09

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

aleks.franca@gmail.com writes:

> ok. I have the solution to my problem. I work with grayscale images
> and they have only 6 diferent pixel values. From 0 to 6. I can
> visualize the image because I created a 6-level-colortable to
> visualize, but when I save it, I cannot see the image because the
> pixel values are very low.
> To save it the way I can actually see the image I have to use the
> command:
>
> image = bytscl(image)
>
> Now I'm confused. Why did that work?

Because now your values are not 0-5, they are this:

IDL> Print, Bytscl(Indgen(6))
0 51 102 153 204 255

And these values show up in the color table you are
using. But this is NOT what you want to do.

What you WANT to do, is load the six colors you are
using to display your image, and scale your image
into those six colors. Something like this:

LoadCT, 33, NCOLORS=6, BOTTOM=1
TV, BytScl(image, TOP=5) + 1B

In general, if you care about colors (and who doesn't!?),
then you should forget you ever heard about TVSCL. :-)

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]

		problem with writing a 2D image .tiff By: aleks.franca@gmail.co on Wed, 18 April 2007 05:54
		Re: problem with writing a 2D image .tiff By: David Fanning on Wed, 18 April 2007 19:08
		Re: problem with writing a 2D image .tiff By: aleks.franca@gmail.co on Thu, 19 April 2007 12:52
		Re: problem with writing a 2D image .tiff By: Jeff N. on Fri, 20 April 2007 08:26
		Re: problem with writing a 2D image .tiff By: aleks.franca@gmail.co on Thu, 03 May 2007 09:58
		Re: problem with writing a 2D image .tiff By: Jeff N. on Fri, 20 April 2007 08:09
		Re: problem with writing a 2D image .tiff By: David Fanning on Thu, 19 April 2007 14:17
		Re: problem with writing a 2D image .tiff By: David Fanning on Thu, 03 May 2007 10:09

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