“…Over the past 20 years, numerous methods have been presented and, in an attempt to bring some order to the diversity of approaches, different reviews, comparisons and classifications have been proposed in the literature (see, for instance, [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]) each one with different criteria and, therefore, with a different categorization. Nevertheless, in the last years, there seems to be a consensus in three main categories, namely Component Substitution (CS), Multi-Resolution Analysis (MRA) and Variational Optimization (VO) [ 15 , 16 , 17 ]. Additionally, the increasing number of Deep Learning (DL)-based pansharpening methods proposed in recent years can be regarded as a new category.…”