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Re: thresholding/color question [message #18782 is a reply to message #18707]

Mon, 07 February 2000 00:00

Alex Schuster
Messages: 124
Registered: February 1997

Senior Member

David Fanning wrote:

> Then, I'd scale my image data like this:
>
> scaledImage = BytScl(image, Top=!D.Table_Size-4)
>
> I'd find the red pixels and assign them like this:
>
> redPixels = Where(image GT threshold, count)
> IF count GT 0 THEN scaledImage[redPixels] = !D.Table_Size-2

Isn"t the usage of WHERE discouraged because of being slow? I always use
direct matrix operation for this, like:

redmask = scaledImage GT threshold
scaledImage = scaled_Image * (1B-redmask) + byte(!D.Table_Size-2) *
redmask

Alex
--
Alex Schuster Wonko@weird.cologne.de PGP Key available
alex@pet.mpin-koeln.mpg.de

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[Message index]

		thresholding/color question By: Patty Howell on Wed, 02 February 2000 00:00
		Re: thresholding/color question By: davidf on Mon, 07 February 2000 00:00
		Re: thresholding/color question By: Alex Schuster on Mon, 07 February 2000 00:00
		Re: thresholding/color question By: davidf on Sat, 05 February 2000 00:00
		Re: thresholding/color question By: Craig Markwardt on Mon, 07 February 2000 00:00
		Re: thresholding/color question By: Alex Schuster on Mon, 07 February 2000 00:00

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