I remember this SO question from the high-contract background point you brought up -- http://stackoverflow.com/questions/36982736/how-to-crop-biggest-rectangle-

I remember this SO question from the high-contract background point you brought up -- http://stackoverflow.com/questions/36982736/how-to-crop-biggest-rectangle-out-of-an-image http://stackoverflow.com/questions/36982736/how-to-crop-bigg...