Apparent Depth Threshold for the Benussi Effect
Using the single staircase psychophysical method, the apparent depth threshold for the Benussi effect was determined for 5 observers. The threshold occurred at an eccentricity of 2r/3, where r equals the radius of the larger circle expressed in millimeters.
Shape, Height and Angular Movement in Stereokinesis
Cues affecting the apparent height (depth) of a stereokinetic ‘cone’ were investigated by comparing heights for pairs of rotating figures. Apparent height was shown to be independent of the number of bands on the figure and of the geometric perspective by which it was drawn. On the other hand, apparent height was strongly dependent on eccentricity within the figure, with maximum apparent height being achieved at full eccentricity. The reason for the existence of such a definite maximum remains obscure.
The perception of three-dimensional structure from rigid and nonrigid motion
The ability of observers to perceive structure from motion was examined for rigid and non-rigid transformations under both parallel and polar projection. The accuracy of form perception was evaluated by asking observers to discriminate among a series of computer-generated surfaces that varied in curvature. The results demonstrated that the accuracy of an observer’s judgments is unaffected by the rigidity of an object’s motion or the type of projection with which it is presented. These results are discussed in relation to current algorithms for computing structure from motion that have recently been described in the literature.