Refer to Problems encountered in training unet and inference unet - #26
and Multiple classes not detected? - #11 by Morganh
Please note that the pixel integer value should be equal to the value of the label_id provided in the spec.
UNet expects the images and corresponding masks encoded as images. Each mask image is a single-channel image, where every pixel is assigned an integer value that represents the segmentation class.
Please inspect each pixel value of the mask image.