I have been using compare and fuzz to find a subset of worst pixels in an image.
In version 7.0.7-11 Q16 x64 2017-11-12 (Windows) the behavior is as expected whereas version 7.0.9-25 Q16 x64 2020-02-21 (Windows) produces a different AE result and doesn’t show all the pixel errors in the hard diff image output.
Compare 2 images with the following command and get a hard diff image with errored pixels highlighted as white against a black background:
Code: Select all
magick compare -verbose -metric ae -fuzz 3.5% -compose src -highlight-color white -lowlight-color black .\source.png .\reference.png fuzz_errors.png
Using histogram check confirmed resultant image contains 5206 white pixelsChannel distortion: AE
Results from 7.0.9-25 Q16 x64 2020-02-21:
Using histogram check there are 0 white pixels, adjusting the fuzz value lower eventually produces pixels in the image but the number does not match the AE resultChannel distortion: AE
Tried searching this issue but not found anything similar so far - perhaps this is an expected change in the fuzz behaviour but I can't quite see how that would be the case.