Characterizing the distribution of completion shapes with corners using a mixture of random processes

We derive an analytic expression for the distribution of contours x(t) gene rated by fluctuations in x(t) = partial derivative x(t)/partial derivative t due to random impulses of two limiting types. The first type are frequent but weak while the second are infrequent but strong. The result has applic ations in computational theories of figural completion and illusory contour s because it can be used to model the prior probability distribution of sho rt, smooth completion shapes punctuated by occasional discontinuities in or ientation (i.e., corners). This work extends our previous work on character izing the distribution of completion shapes which dealt only with the case of frequently acting weak impulses. (C) 2000 Pattern Recognition Society. P ublished by Elsevier Science Ltd. All rights reserved.