Legacy ImageMagick Discussions Archive

Ah so it looks like the main reason i was struggling was because i thought -compose difference would also diff the alpha channel. Looks like magick by default only uses rgb for its operators unless told (default setting is: RGBK,sync ) Quick question: Why is it necessary to reset the channel ...

Spent a bit of time to make a test image (below) and it looks like your most recent script does just as well as compare does. I just have to add threshold 0 at the very end for my own use-case since i end up multiplying this mask later on. Would you mind explaining why it works, though? Thanks so ...

Yeah, that is really close to perfect. The regions are slightly off but this should be fine. Think ill run with this.

Thank you both very much

Let me clarify what i mean by anything . If i was given current-frame.png and asked to circle any pixels that have changed since previous-frame.png , that is what the output would be. I was basically looking for a way to emulate the compare command with convert in order to avoid writing a temporary ...

I'd want exactly like the above. Wherever anything is different: white, otherwise black.

Ah that works perfectly, thanks. I forgot to mention in my original post, though, that these images don't have to be 100% black; that was just an edge case I found. Do you have a solution for a case like this?: Previous: http://puu.sh/r0Yku/50f67483c6.png Current: http://puu.sh/r0YlQ/f5d451a85f.png ...

I am trying to find the difference between images that are only black and transparent. Since compose difference is just abs(src - dest), using threshold 0 to generate a "difference mask" fails. convert current-frame.png -compose difference -composite -threshold 0 difference-mask.png Is there a way ...