Compare - scaled highlight

[oddeven21]

Hi all,

Using the compare tool, i'm wondering if there is a way to have the highlight color scale based on the delta? For example, the larger the difference is between two pixels, the darker the highlight color is.

compare -metric ae a.png b.png diff.png

Thanks!

[fmw42]

Not with compare. But you can do it with -compose difference. try this

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convert image1 image2 \
\( -clone 0 -function polynomial "0.5 0.5" \) \
\( -clone 0 -fill red -colorize 100 \) \
\( -clone 0 -clone 1 -compose difference -composite -colorspace gray -write show: \) \
-delete 0,1 -compose over -composite result

Adjust -function polynomial to make the background image fade as desired so that you can see the red colorization or make the background image black to just show the difference.

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convert image1 image2  \
\( -clone 0 -fill black -colorize 100 \) \
\( -clone 0 -fill red -colorize 100 \) \
\( -clone 0 -clone 1 -compose difference -composite -colorspace gray -write show: \) \
-delete 0,1 -compose over -composite show: 

or to see the color differences in each channel

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convert logo: logo_blur.png -compose difference -composite -auto-level show: 

see
http://www.imagemagick.org/Usage/compare/#difference