Research Article The Perception of Doubly Curved Surfaces From Anisotropic Textures.pdfVIP

PSYCHOLOGICAL SCIENCE Research Article The Perception of Doubly Curved Surfaces From Anisotropic Textures James T. Todd, 1 Augustinus H.J. Oomes,1 Jan J. Koenderink,2 and Astrid M.L. Kappers2 1Ohio State University and 2Helmholtz Instituut, Universiteit Utrecht, Utrecht, The Netherlands ABSTRACT—Most existing computational models of the visual attributed to variations in the surface geometry (e.g., depth, slant, or perception of three-dimensional shape from texture are based on curvature). For purposes of the present discussion, it is useful to ca- assumed constraints about how texture is distributed on visible tegorize textures into two general classes that we refer to, respectively, surfaces. The research described in the present article was de- as blob textures and contour textures. Blob textures are those that signed to investigate how violations of these assumptions influ- contain patterns of discrete shapes such as polka dots or flagstones, ence human perception. Observers were presented with images whereas contour textures contain patterns of extended lines, as in of smoothly curved surfaces depicted with different types of wood veneer or striped cloth. texture, whose distribution of surface markings could be both The earliest computational analyses of 3D shape from texture were anisotropic and inhomogeneous. Observers judged the pattern designed primarily for blob textures, based on an assumption that the of ordinal depth on each object by marking local maxima and sizes and shapes of these blobs on a physical surface are approxi- minima along designated scan lines. They also judged the ap- mately uniform. Texture gradients are defined in this context