Thank you for your reply,
Actually, I am dealing with the UNet model for multiclass segmentation task. The datasets are quite the same, same size and pixels, only the grid change a little bit. I have 25 types of ground-truth/mask and 4 different shapes of tumour that I can add to it. But I can not repeat the ground-truth types. I was thinking to use the ensemble approach because my dataset is very small (n=25). I saw this paper [1711.01468] Ensembles of Multiple Models and Architectures for Robust Brain Tumour Segmentation 2 discussing it, but I did not fully understand.
Best,
Giulia