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Re: Array indices and lookup tables [message #39713 is a reply to message #39712]

Thu, 10 June 2004 06:57

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Haje Korth writes:

> oops, you are right, the 360 should have been a 720. I have worked with
> triangulate and trigrid in the past and what I learned is that you do NOT
> use these in time-critical operations. This is even slower than looping
> through a lookup table.

Well, if that's the case, then here is an example that works,
more or less:

IDL> filename = Filepath(Subdir=['examples', 'data'], 'rose.jpg')
IDL> Read_JPEG, filename, rose
IDL> help, rose
ROSE BYTE = Array[3, 227, 149]
IDL> a=indgen(227,149) ; Look-up table
IDL> a = shift(a, 100) ; Shift it so it looks different
IDL> r = bytarr(3, 227, 149) ; The new image, r.
IDL> r[0,*,*] = (rose[0,*,*])[a]
IDL> r[1,*,*] = (rose[1,*,*])[a]
IDL> r[2,*,*] = (rose[2,*,*])[a]
IDL> window, xsize=2*227, ysize=149
IDL> tv, rose, 0, true=1
IDL> tv, r, 1, true=1

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/

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[Message index]

		Re: Array indices and lookup tables By: David Fanning on Thu, 10 June 2004 06:59
		Re: Array indices and lookup tables By: David Fanning on Thu, 10 June 2004 06:57
		Re: Array indices and lookup tables By: Haje Korth on Thu, 10 June 2004 06:11
		Re: Array indices and lookup tables By: Chris Lee on Thu, 10 June 2004 01:39
		Re: Array indices and lookup tables By: Haje Korth on Wed, 09 June 2004 07:49
		Re: Array indices and lookup tables By: David Fanning on Wed, 09 June 2004 07:26
		Re: Array indices and lookup tables By: Haje Korth on Wed, 09 June 2004 07:06
		Re: Array indices and lookup tables By: David Fanning on Wed, 09 June 2004 06:42
		Re: Array indices and lookup tables By: Chris Lee on Thu, 10 June 2004 10:15

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