comp.lang.idl-pvwave archive: archive » thresholding/color question

Home » Public Forums » archive » thresholding/color question

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: thresholding/color question [message #18779 is a reply to message #18707]

Mon, 07 February 2000 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Alex Schuster (alex@pet.mpin-koeln.mpg.de) writes:

> Isn"t the usage of WHERE discouraged because of being slow?

If it is, it's news to me. :-)

> I always use direct matrix operation for this, like:
>
> redmask = scaledImage GT threshold
> scaledImage = scaled_Image * (1B-redmask) + byte(!D.Table_Size-2) *
> redmask

I don't doubt there are speed advantages in matrix operations,
but unless you had a huge image I doubt very much you
would notice. And even then, the increase in speed would probably
be more than offset by the additional memory usage.

Plus, I don't have a clue what this code is doing when I
read it! Simple things for simple folk, is my motto. :-)

Cheers,

David

P.S. If my memory serves, Alex, aren't you the one with
the 10 quadrillion Megs of RAM on your machine? Perhaps
matrix operations *are* the best thing for you. :-)
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

Report message to a moderator

[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

Previous Topic:	Re: Cannot save MPEG
Next Topic:	Q: Scientific notation in Obj. graphics

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sun Oct 12 10:41:26 PDT 2025

Total time taken to generate the page: 0.80033 seconds