A CLOSED CURVE IS MUCH MORE THAN AN INCOMPLETE ONE - EFFECT OF CLOSURE IN FIGURE GROUND SEGMENTATION

Detection of fragmented closed contours against a cluttered background occurs much beyond the local coherence distance (maximal separation between segments) of nonclosed contours. This implies that the extent of interaction between locally connected detectors is boosted according to the global stimulus structure. We further show that detection of a target probe is facilitated when the probe is positioned inside a dosed circle. To explain the striking contour segregation ability found here, and performance enhancement inside dosed boundaries, we propose the existence of a synergetic process in early vision.