Nonscalar Mathematical Morphology

Mathematical morphology is not always straightforward to generalize to situations where values in an image do not admit a natural total order. This mostly due to the limitations of the underlying formalism. Three state-of-the-art solutions for bypassing those limitations are discussed, with example applications ranging from color images interpreted as vector spaces to periodic and hyperbolic value spaces, and categorical data stemming from per-pixel classification of remote sensing images.