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Re: frequency distribution and bytscl [message #31377 is a reply to message #31376]

Wed, 10 July 2002 08:44

mchinand
Messages: 66
Registered: September 1996

Member

In article <aghiu4$kcb$1@newsreader.wustl.edu>,
Sean Raffuse <sean@me.wustl.edu> wrote:
> Hello,
>
> I want to stretch an image based on it's frequency distribution:
> stretched_image = bytscl(image, min=low, max=high)
> where low is the bottom 5th percentile and high is the upper 5th percentile.
> How can I get the values of the x percentile of a given array?
> thanks in advance,
>
> Sean
>

I think the PERCENT option of HIST_EQUAL function will do what you want.
It uses histogram and then TOTAL(histo,/CUMULATIVE) to find the cutoff
points.

Hope that helps,

--Mike

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Michael Chinander University of Chicago
m-chinander@uchicago.edu (773)834-5101 (Voice) (773)702-0371 (Fax)

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[Message index]

		Re: frequency distribution and bytscl By: mchinand on Wed, 10 July 2002 09:43
		Re: frequency distribution and bytscl By: Liam E. Gumley on Wed, 10 July 2002 09:09
		Re: frequency distribution and bytscl By: mchinand on Wed, 10 July 2002 08:44

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