CONTOUR DESCRIPTOR PROPERTIES OF VISUAL SHAPE.
Final rept. 1 Feb 66-31 Jan 67,
SPERRY RAND RESEARCH CENTER SUDBURY MASS
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The results of a one year program to elucidate the problems underlying shape perception are presented. Following a review of the field, extensive studies of spontaneous fixation tendencies in visual forms are reported. These studies indicate that visual shape is a stimulus to fixation, suggesting that the peripheral inputs, per se, are not the primary determiners of spontaneous fixation tendencies, but that the already organized cortical representation of shape is such a factor. Experiments will flow patterns in visual noise suggest that the visual system does behave as if it has field or global properties. Finally, studies of illusions indicate that a second class of visual illusions can be designated on the basis of dependency on converging lines or line segments as the inducing feature. Illusions in this inclination-dependent class are all such that if the illusion inducing lines are rotated so they are parallel or normal to the test lines the illusion is eliminated. This classification permits a number of apparently different illusions, including the Hering, Zollner, and Ponzo illusions, to be considered related. Author