Fig. 9:

UNet++ enables a better optimization than U-Net evidenced by the learning curves for the tasks of neuronal structure, cell, nuclei, brain tumor, liver, and lung nodule segmentation. We have plotted the validation losses averaged by 20 trials for each application. As seen, UNet++ with deep supervision accelerates the convergence speed and yields the lower validation loss due to the new design of the intermediate layers and dense skip connections.