matlab - How to calculate variance of an image patch with vectorization -


i have 560*560*3 image file, want divide image many small 8*8 patches, calculate variance of each patch. vectorized way calculate variance of each image patch matlab or octave?

you can use nfilter function:

  fun = @var;   b = nlfilter(a, [8 8], fun);

by way, if wanted 3x3 image patches, use stdfilt function . left apply square on image:

  s = stdfilt(im);   s = s.*s;

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