ImageStat.Stat.extrema reports 0,255 on 16 bit grey image #1606

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1. radarhere commented on Dec 23, 2015

   

   radarhere

   on Dec 23, 2015

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   No, testing with the latest version, I get the same result.
2. wiredfool commented on Dec 27, 2015

   

   wiredfool

   on Dec 27, 2015

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   There is an Image.getextrema function, which returns the per-band extrema for the image.

   This function is used by the histogram function for non 8-bit modes to return extrema to define the bins used in the histogram. The histogram is still going to return a vector length = bands*256.

   ImageStat.Stat.extrema relies on the image histogram function, and simply returns the low and high bins used. This is correct for 8 bit per channel images, but fails for anything else.

   So, ultimately, Image.getextrema is a much more efficient and correct function to use.
3. wiredfool

   added

   Enhancement

   Documentation

   on Dec 29, 2015
4. wiredfool

   added this to the 3.2.0 milestone on Dec 29, 2015
5. wiredfool commented on Dec 29, 2015

   

   wiredfool

   on Dec 29, 2015

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   • Document the format limitations of ImageStat
   • Document the much more efficient Image.getextrema function
   • Alternately, pop a warning or clear no data on I or F images
6. radarhere

   removed this from the 3.2.0 milestone on Jan 6, 2017
7. hugovk

   closed this as completedin #3661on May 3, 2019
8. aclark4life

   added

   PNG

   on Oct 8, 2026