A Study of the Pattern Recognition for the Visually Impaired

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 10610074
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 実験系心理学
• Research Institution: Kochi University
• Principal Investigator: FUJITA Naofumi Department of Education, Kochi University Professor, 教育学部, 教授 (10165384)
• Project Period (FY): 1998 – 2000
• Keywords: touch / illusion / convex / concave

Research Abstract

We examined the various effects of the curvature of the surfaces, including whether the surface was convex or concave ; whether the surface was upward or downward ; whether the surface was leftward or rightward ; or whether the standard stimulus was located left of the comparison stimulus or not. All the surfaces used were 2 dimensional. The subject sat in front of the table with eyes masked and touched the stimuli with the right hand. The subject was given the standard and comparison stimuli simultaneously. The task of the subject was to choose the higher (or deeper) stimulus. To obtain the PSE, the method of limits was used. The convex and concave surface consisted of the sine curve. The standard stimulus was 5.1 cm in width and 1.0 cm in height (or depth). The comparison stimuli were 3.4 cm in width and had 15 kinds of height (or depth) ranging 0.1 cm to 1.5 cm. The following results were obtained.
(1)The surface with 3.4 cm in width was constantly perceived higher or deeper than the surface with 5.1 cm in width. (2) When the standard stimulus was downward, the height was overestimated. When it was leftward, the height was underestimated. (3) When the surface was 3.4 cm in width, the convex one was perceived higher than the concave one. (4) When the stimuli were different in terms of the width or curvature, the comparison stimulus was perceived higher.
When the subject touched the convex surface, the finger passed the outside of the surface. When the subject touched the concave surface, the finger passed the inside of the surface. This difference of the trajectory may cause the difference of the perceived height.
The direction of the surface made the difference of the perceived height, which might be related to the apparent difference of the flat surfaces at the both sides of the curved surface.