Shape descriptors computed from photographs of dolphin dorsal fins for use as database indices

Field photographs of bottlenosed dolphins (Tursiops truncatus) are used for identification of individuals based on notches that are present in the fin; comparison by eye with a collection of photographs is commonly used but is cumbersome. A system is reported here that extracts from photographs a set of features describing the pattern of notches in the fin; these features will be used to index an image database. A method based on modeling the fin edge with an affine invariant Fourier transform was tested but was not successful. A method based on notch location with a stiff snake followed by Gaussian curve fitting, however, produced a promising set of features