Lr. Williams et Dw. Jacobs, STOCHASTIC COMPLETION FIELDS - A NEURAL MODEL OF ILLUSORY CONTOUR SHAPE AND SALIENCE, Neural computation, 9(4), 1997, pp. 837-858
We describe an algorithm- and representation-level theory of illusory
contour shape and salience. Unlike previous theories, our model is der
ived from a single assumption: that the prior probability distribution
of boundary completion shape can be modeled by a random walk in a lat
tice whose points are positions and orientations in the image plane (i
.e., the space that one can reasonably assume is represented by neuron
s of the mammalian visual cortex). Our model does not employ numerical
relaxation or other explicit minimization, but. instead relies on the
fact that the probability that a particle following a random walk wil
l pass through a given position and orientation on a path joining two
boundary fragments can be computed directly as the product of two vect
or-field convolutions. We show that for the random walk we define, the
maximum likelihood paths are curves of least energy, that is, on aver
age, random walks follow paths commonly assumed to model the shape of
illusory contours. A computer model is demonstrated on numerous illuso
ry contour stimuli from the literature.