Because some CDs are effectively mirrors, I've taken photos at an angle, using a backing white sheet to capture that mirror part cleanly. But this means that I can't use MobyCairo, as it doesn't correct the angle, and so can't detect the circle for cropping afterwards.
This should be correctable using "homography" as described here, in an additional step:
https://stackoverflow.com/questions/25724923/opencv-how-do-i-implement-keystone-correction
Test Image
Because some CDs are effectively mirrors, I've taken photos at an angle, using a backing white sheet to capture that mirror part cleanly. But this means that I can't use MobyCairo, as it doesn't correct the angle, and so can't detect the circle for cropping afterwards.
This should be correctable using "homography" as described here, in an additional step:
https://stackoverflow.com/questions/25724923/opencv-how-do-i-implement-keystone-correction
Test Image