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What is like CONGRID, but averages on reduction? [message #5108]

Tue, 10 October 1995 00:00

grunes
Messages: 68
Registered: September 1993

Member

Subject: What is like CONGRID, but averages on reduction?

I need to reduce the size of an array by an arbitrary (non-integral)
factor, using an averaging algorithm. Is there such a routine
in IDL and/or PV-WAVE?

When I display an image that is larger than the window, I use:

A=REBIN(A,XSZ,YSZ)
or
A=CONGRID(A,XSZ,YSZ)

The problem with REBIN is that XSZ and YSZ must be integral factors
of the size of A. This means that I often can not take advantage
of the whole screen. But it is able to average things down (as
long as I don't set /SAMPLE), so bright and dark points don't get
lost.

The problem with CONGRID is that it sometimes misses bright or
dark spots altogether. For example:
A=INTARR(9,9)
A(3,3)=1
PRINT,CONGRID(A,4,4)
or
PRINT,CONGRID(A,4,4,/INTERP)
misses the bright point, because CONGRID can interpolate or use
nearest neighbor, but cannot average.

Thanks in advance.

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[Message index]

		What is like CONGRID, but averages on reduction? By: grunes on Tue, 10 October 1995 00:00
		Re: What is like CONGRID, but averages on reduction? By: thompson on Mon, 16 October 1995 00:00
		Re: What is like CONGRID, but averages on reduction? By: grunes on Thu, 12 October 1995 00:00
		Re: What is like CONGRID, but averages on reduction? By: thompson on Wed, 11 October 1995 00:00

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