“…In recent years, learning-based SR methods [3] have been extensively studied, which use a learned co-occurrence to predict the correspondence between LR and HR patches. The learning algorithms including Markov network [4,5,6], neighbor embedding [7,8,9,10], dictionary learning [11,12,13,14], anchored neighborhood regression [16,15], random forests [17], and deep learning [18,19,20,21].…”