A Probabilistic Contour Discriminant for Object Localisation

A method of localising objects in images is proposed. Possible conngurations are evaluated using the contour discriminant, a likelihood ratio which is derived from a probabilistic model of the feature detection process. We treat each step in this process probabilistically, including the occurrence of clutter features, and derive the observation densities for both correct \target" con-gurations and incorrect \clutter" conngurations. The contour discriminant distinguishes target objects from the background even in heavy clutter, making only the most general assumptions about the form that clutter might take. The method generates samples stochasti-cally to avoid the cost of processing an entire image, and promises to be particularly suited to the task of initialising contour trackers based on sampling methods .