| Re: Overlay a coloured boundary on a gray scale image [message #81749 is a reply to message #81651] |
Fri, 12 October 2012 05:35  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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titan writes:
> probably my question is not clear :( and I'm sorry for this.
> I try to explain it better:
>
> I'm able to read a shapefile from which I'm able to obtain the corresponding image which is a binary one. Then I can extract those subscripts values where the boundary is
>
> boundary_index = WHERE(boundary_array NE 0)
>
> my gray scale image has the same dimension of the boundary image and as a consequence I can draw the line over it (in white)
>
> image[boundary_index]=255
>
> What I would like to do i to understand if I could draw this line not in white but in another color, for example yellow.
>
> Is there this possibility?
I presume you are using indexed color to display your image.
Simply load your image colors into indices 0 to 254 and
use color index 255 to load whatever color you like.
I would do it like this:
LoadCT, 0, NColors=254
TVLCT, 255, 255, 0, 255 ; Yellow in index 255
scaledImage = BytScl(image, TOP=254
scaledImage[bounary_index] = 255
cgImage, scaledImage
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thue. ("Perhaps thos speakest truth.")
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