Just tried it on my old app and it worked well :) I think you'll have to roll your own rectangle detection and use heuristics to make it better. So in mine I

Just tried it on my old app and it worked well :) I think you'll have to roll your own rectangle detection and use heuristics to make it better. So in mine I assume that the connected object in the thresholded image with the largest number of pixels must be the puzzle. That makes it a lot easier. Good luck!