A Markov random field model of subjective contour perception

We describe a model of subjective contour perception that sees the triangle: top-down feedback from the perception of an occluding object causes the perception of illusory contrast along the object's boundary. Unlike other approaches, the model explicitly incorporates a representational hierarchy of visual elements at multiple levels of abstraction, for example, both local contrast edges and triangles. The model is a connectionist network implemented within the formal framework of Markov random fields, which provides for bidirectional information flow over connections. Simulation results show how feedforward activation yields the perception of the occluding triangle at a high-level of abstraction, and how feedback activates the units that represent the illusory contrast.