possible bug compare -metric AE for IM 6.9.7.7 Q16 Mac OSX

[fmw42]

I have these two images from the link at the discussion at viewtopic.php?f=1&t=31374#p142609






If I use MAE for the search, it works fine and I get

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compare -metric MAE -subimage-search f81dM.png FSDKC.png diffimage.png
1994.08 (0.0304277) @ 5,0

But if I use AE, I get an error message even with -dissimilarity-threshold 1. That seems to be a bug, since setting -dissimilarity-threshold 1 should permit any dissimilarity. Is that not correct?

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compare -metric AE -subimage-search -dissimilarity-threshold 1 f81dM.png FSDKC.png diffimage.png

compare: images too dissimilar `f81dM.png' @ error/compare.c/CompareImageCommand/986.

[magick]

Most metrics are normalized, AE is not. The dissimilarity threshold is relative to your metric. For AE and this sequence, use -dissimilarity-threshold 120000.

[fmw42]

Thanks. Is the dissimilarity-threshold needed for AE in raw values or normalized values. If I want to compute the worst possible value, then would it be total pixels in the image times 1 or times quantumvalue?