There is nothing innovative here. And with the kind of images that they are considering, you could simply use a Canny edge detector and take the outer-most cont

There is nothing innovative here. And with the kind of images that they are considering, you could simply use a Canny edge detector and take the outer-most contour to be the region of interest. As the previous comments have said, this is a well tackled problem. They must have done some literature survey.