Distances in multimedia phylogeny

The distance between two objects determines how far apart they are with respect to each other. In this paper, we provide an overview of the distance concept in multimedia phylogeny, a novel research field that aims at discovering the phylogenetic relationships among digital objects that belong to the same population. With applications in digital forensics, copyright enforcement, and security, existing approaches are often based on dissimilarity computations among digital objects in a nonmetric space, but with enough information to correctly reconstruct the underlying relationships of these objects. As we discuss throughout the paper, a proper and well-designed dissimilarity is paramount for differentiating whether two multimedia objects are related and, also, the directionality of such relationship. In phylogeny setups, there is also the additional requirement of low complexity: fast and accurate dissimilarity measures to cope with the massive amount of data we often have to handle. (AU)