Study on 3-D anorthoscopic perception

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04610061
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Psychology
• Research Institution: Kochi University
• Principal Investigator: FUJITA Naofumi Kochi Univ.Faculty of Education, Associate Professor, 教育学部 (10165384)
• Project Period (FY): 1992 – 1993
• Keywords: Anorthoscopic perception / Computational theory / 3-D object / Underestimation of velocity

Research Abstract

Why is the figure behind the slit perceived as distorted? This question, which Helmholtz raised about a hundred years ago, is explained as follows : (1) The acute angle subtending between the contour of the figure and the edges of the slit is overestimated so that the velocity of the figure is overestimated at a constant ratio (=a). (2) When the figure passes across the either edge of the slit, the velocity is underestimated as v' by means of the addition (=b) of the perceived traverse time (t'). (3) The ratio of distortion (R) is defined as (perceived traverse distance) / (physical traverse distance) with the result that R=v'/v=t/t'. We found that t'=a t + b. Therefore, R=t/ (a t +b).
It is not only 2-D figures but also rotating 3-D figures that we perceive veridically when they pass behind the slit. Under the constraints of the rigidity, the constant angular velocity, and the fixed rotational axis, the depth of the figure is computationally restored if three points of the figure are given three times. Especially, it is suggested that the velocity along the y-aixs plays a major role when the figure passes along and rotates about the x-axis. We examined the perceived depth of the cone consisting of the line segments which rotated about the x-axis, and found that the perceived depth increased as the angular velocity and as the number of the line segments. The perceived depth had a close correlation with the sum of the y-velocity of each line segment.