1. An image enhancement process comprising the steps of: a windowing process that selects a sub region of an image; determining a value for each of one or more characteristics of the sub region, the characteristics being of a subject of the sub region; defining one or more classes of the sub region from the values; selecting one or more transform filters obtained using the learning/training process, that corresponds to each class; and successively applying the transform filter to the sub region having the same class as the transform filter to obtain a transformed sub region.