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Re: Random convolution ? [message #40092 is a reply to message #40090]

Thu, 08 July 2004 07:30

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Emmanuel Christophe writes:

> I got a random effect using convolution:
>
> ------------------------------------------------------
> imagetest=indgen(256,256,224)
> ker=indgen(1,3,5)
> r1=convol(double(imagetest),double(ker),/edge_truncate)
> r2=convol(double(imagetest),double(ker),/edge_truncate)
> r3=convol(double(imagetest),double(ker),/edge_truncate)
> print, max(abs(r1-r2))
> print, max(abs(r1-r3))
> print, max(abs(r2-r3))
> end
> ------------------------------------------------------
>
> The first time, I got
> IDL> .GO
> 85.961538
> 793.00000
> 768.00000
>
> and the second time:
> IDL> .GO
> 793.00000
> 793.00000
> 0.0000000
>
> And all results should be zero... I suspect a memory effect but how ?

Don't know. I get all zeros every time I run this.

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: Random convolution ? By: R.G. Stockwell on Fri, 09 July 2004 08:25
		Re: Random convolution ? By: Emmanuel Christophe on Thu, 08 July 2004 23:03
		Re: Random convolution ? By: Chris[2] on Thu, 08 July 2004 15:30
		Re: Random convolution ? By: K. Bowman on Thu, 08 July 2004 13:28
		Re: Random convolution ? By: R.G. Stockwell on Thu, 08 July 2004 10:21
		Re: Random convolution ? By: David Fanning on Thu, 08 July 2004 08:20
		Re: Random convolution ? By: Emmanuel Christophe on Thu, 08 July 2004 07:50
		Re: Random convolution ? By: David Fanning on Thu, 08 July 2004 07:30

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