I am training a U-Net image segmentation on whole CT & MRI images. how can I handle un-annotated areas? I am working with huge tissues and it’s impossible to annotate all or the vast majority of the tissue, Aim annotated selected tissue structures of interest to me. That means that in many polygon (mesh) I’m generating, there is a segment that’s not annotated.
Would it affect the U-Net negatively by indirectly indicating that the un-annotated area is negative to one category or another, although it’s not negative? How do I handle this important case? Does it make sense to mask the image to only the annotated parts, such that un-annotated regions are black?