Use of Mask in U Net for plant disease detection

I am using U-Net for plant disease detection.I am new to deep learning and computer vision. I need to know the use of image masking in image segmentation using U-Net, why it is needed? What kind of Masking do we need to feed to the architecture?

Currently, I'm feeding the masking images generated via open cv HSV format to detect colours from the images so that the background and foreground are detected. Is it the correct approach? Or Do we …

deeplearning detection disease