I have images like rice, fish and spinach. I've attached some images. I'm planning to do masking to the images automatically but I only know how to do masking using imfreehand as they got irregular shapes. I want to use masking because i want to get the ROI only. Background will be removed and set to black colour.
For example, i want to do masking to the rice image, and my ROI is the white part of the rice only. Can someone help how to make the images masked automatically?