Conveying 3D Shape with Texture: Recent Advances and Experimental Findings
Author(s): Victoria Interrante, Sunghee Kim, Haleh Hagh-Shenas.
Proceedings: Proc. SPIE, Human Vision and Electronic Imaging VII, Bernice E. Rogowitz, Thrasyvoulos N. Pappas, Vol. 4662, pp. 197--206, May,
2002.
[BibTeX] 
Abstract:
If we could design the perfect texture pattern to apply to any smooth surface in order to enable observers to more
accurately perceive the surface's shape in a static monocular image taken from an arbitrary generic viewpoint under
standard lighting conditions, what would the characteristics of that texture pattern be? In order to gain insight into this
question, our group has developed an efficient algorithm for synthesizing a high resolution texture pattern, derived from
a provided 2D sample, over an arbitrary doubly curved surface in such a way that the orientation of the texture is
constrained to follow a specified underlying vector field over the surface, at a per-pixel level, without evidence of seams
or projective distortion artifacts. In this paper, we report the findings of a recent experiment in which we attempt to use
this new texture synthesis method to assess the shape information carrying capacity of two different types of directional
texture patterns (unidirectional and bi-directional) under three different orientation conditions (following the first
principal direction, following a constant uniform direction, or swirling sinusoidally in the surface). In a four alternative
forced choice task, we asked participants to identify the quadrant in which two B-spline surfaces, illuminated from
different random directions and simultaneously and persistently displayed, differed in their shapes. We found, after all
subjects had gained sufficient training in the task, that accuracy increased fairly consistently with increasing magnitude
of surface shape disparity, but that the characteristics of this increase differed under the different texture orientation
conditions. Subjects were able to more reliably perceive smaller shape differences when the surfaces were textured with
a pattern whose orientation followed one of the principal directions than when the surfaces were textured with a pattern
that either gradually swirled in the surface or followed a constant uniform direction in the tangent plane regardless of the
surface shape characteristics. These findings appear to support our hypothesis that anisotropic textures aligned with the
first principal direction may facilitate shape perception, for a generic view, by making more, reliable information about
the extent of the surface curvature explicitly available to the observer than would be available if the texture pattern were
oriented in any other way.