“…Variational models, based on optimizing energy functionals, have been widely investigated, proving to be very effective on different images; curve evolution [4], anisotropic diffusion [5] and the Mumford-Shah model [6] are good representatives of these methods. Other recent approaches to image segmentation include learning-based methods, which often exploit deep-learning techniques [7][8][9], watershed [10], random walk methods [11], graph cuts [12,13], epidemiological models on images [14]. However, in this case, a large amount of data must be available to train learning networks, thus making those approaches impractical in some applications.…”