[Octave-bug-tracker] [bug #54614] [octave forge] (image) wrong results of entropyfilt

[Avinoam Kalma]

Follow-up Comment #2, bug #54614 (project octave):

Thanks for pointing me related bugs, however, I found some other problems:

Checking entropyfilt, there are two problems in __spatial_filtering__.cc

The normalization of the histogram is wrong. Instead of


  for (octave_idx_type i = 0; i < len; i++)
    hist (vals (i) + add) /= (double)len;


the loop should be


  for (octave_idx_type i = 0; i < nbins; i++)
    hist (i) /= (double)len;


Another problem is in the transfer of data from the matrix:
It seems that the line


         values_fvec[se_ind] = in(in_sub) + heights_fvec[se_ind];


is wrong, and should be replaced by


         values_fvec[se_ind] = in(in_sub) ;


(Can someone confirm this?) 
This change affects also stdfilt, rangefilt, and ordfiltn.

Changeset attached, including relevant tests in entropyfilt.m

Please review.

(file #44959)
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File name: bug_54614_V1.cs                Size:1 KB


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