title: A model of natural image edge co-occurrence in the rototranslation group.
abstract: In this paper, we propose to model the edge information contained in natural scenes as points in the 3D space of positions and orientations. This space is equipped with a strong geometrical structure and it is identified as the rototranslation group. In this space, we compute a histogram of co-occurrence of edges from a database of natural images and show that it can be interpreted as a probability density function, expressed by the fundamental solution of a suitable Fokker-Planck equation defined in the 3D structured space. Both estimated statistics and model predictions are reconsidered and compared with the partial gestalt association fields proposed by D. J. Field, A. Hayes, and R. F. Hess (1993). Finally, parametric identification allows to estimate the variance of the co-occurrence random process in natural images.
authors.affiliation: Instituto de Ingeniería Eléctrica (IIE), Universidad de la República,Montevideo, Uruguay. gsangui@ding.edu.uy
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Sanguinetti
authors.forename: Giovanna
authors.initials: G
authors.lastname: Citti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sarti
mesh_terms: D015350:Contrast Sensitivity / Q000502:physiology*; D003867:Depth Perception / Q000502:physiology; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D013269:Stochastic Processes; D014793:Visual Cortex / Q000502:physiology*