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From: cs450a03@uc780.umd.edu
Newsgroups: comp.lang.apl
Subject: RE: Histogram
Message-ID: <31MAR91.18441674@uc780.umd.edu>
Date: 31 Mar 91 18:44:16 GMT
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Ken Block writes:
>What would be an efficient way to generate a histogram? I have a
>64x64 greyscale (0 to 255) image and I need the frequencies. The
>obvious methods produce large amounts of data O(64*64*265) and cause
>the machine thrash.  Any suggestions...

I can think of two easy solutions.  (1) break that 64x64 image into
smaller pieces, apply your code to each piece and assemble the
results.  (2) I'm not sure what kind of histogram you are trying to
generate, but can't you just ravel the image data, sort the
intensities, then find the length of each partition?

Raul