Information along contours and object boundaries
Jacob Feldman and Manish Singh
Psychological Review, 112, 243-252
Attneave (1954) famously suggested that information along visual contours is concentrated in regions of high magnitude of curvature, rather than being distributed uniformly along the contour. Here we give a formal derivation of this claim, yielding an exact expression for information, in Shannon’s sense, as a function of contour curvature. Moreover, we extend Attneave’s claim to incorporate the role of sign of curvature, not just magnitude of curvature. In particular, we show that for closed contours, such as object boundaries, segments of negative curvature (that is, concave segments) literally carry greater information than corresponding regions of positive curvature (i.e., convex segments). The psychological validity of our informational analysis is supported by a host of empirical findings demonstrating the asymmetric way in which the visual system treats regions of positive and negative curvature.