Curvature and separation discrimination at texture boundaries.

Visual discrimination of contour curvature was investigated by using contours defined by the locus of points at which the phase of a square-wave grating was shifted by 180 degrees (a texture boundary). Curvature-increment thresholds were measured for contour curvatures from 0.31 to 10.65 deg-1, for grating spatial frequencies of 4.0 and 16.0 cycles per degree (cpd), and for gratings in either sine or cosine phase at the point of maximum curvature. Thresholds for these conditions were compared with curvature discrimination at black-white edges. Grating phase had no effect on performance at any curvature or grating frequency, but 16.0-cpd gratings produced a threshold elevation at all curvatures by an average factor of 2.4. Two-line separation discrimination was also measured for lines defined by texture boundaries. These data can be predicted by a model incorporating end-stopped complex cells of a type reported physiologically in primate area V2.

[1]  M. Morgan,et al.  Biases and sensitivities in geometrical illusions , 1990, Vision Research.

[2]  Quick Rf.  A vector-magnitude model of contrast detection. , 1974 .

[3]  H. Wilson,et al.  Orientation bandwidths of spatial mechanisms measured by masking. , 1984, Journal of the Optical Society of America. A, Optics and image science.

[4]  Gerald Westheimer.  Line-separation discrimination curve in the human fovea: smooth or segmented? , 1984 .

[5]  Dennis M. Levi,et al.  “Weber's law” for position: Unconfounding the role of separation and eccentricity , 1988, Vision Research.

[6]  J Nachmias,et al.  Letter: Grating contrast: discrimination may be better than detection. , 1974, Vision research.

[7]  Hugh R. Wilson,et al.  Responses of spatial mechanisms can explain hyperacuity , 1986, Vision Research.

[8]  A. Hendrickson,et al.  Distribution of cones in human and monkey retina: individual variability and radial asymmetry. , 1987, Science.

[9]  R. Watt,et al.  The recognition and representation of edge blur: Evidence for spatial primitives in human vision , 1983, Vision Research.

[10]  D. P. Andrews,et al.  Contour curvature analysis: Hyperacuities in the discrimination of detailed shape , 1982, Vision Research.

[11]  W Richards,et al.  Encoding contour shape by curvature extrema. , 1986, Journal of the Optical Society of America. A, Optics and image science.

[12]  S. Zucker,et al.  Endstopped neurons in the visual cortex as a substrate for calculating curvature , 1987, Nature.

[13]  S. McKee,et al.  Spatial configurations for visual hyperacuity , 1977, Vision Research.

[14]  R. von der Heydt,et al.  Illusory contours and cortical neuron responses. , 1984, Science.

[15]  Donald D. Hoffman,et al.  Parts of recognition , 1984, Cognition.

[16]  Jan J. Koenderink,et al.  Two-dimensional curvature operators , 1988 .

[17]  D. Foster,et al.  Discrete and continuous modes of curved-line discrimination controlled by effective stimulus duration. , 1986, Spatial vision.

[18]  F. Attneave.  Some informational aspects of visual perception. , 1954, Psychological review.

[19]  B. Julesz,et al.  Human factors and behavioral science: Textons, the fundamental elements in preattentive vision and perception of textures , 1983, The Bell System Technical Journal.

[20]  J. M. Foley,et al.  Contrast masking in human vision. , 1980, Journal of the Optical Society of America.

[21]  S. Zucker,et al.  Endstopping and curvature , 1989, Vision Research.

[22]  D. Hubel,et al.  Receptive fields and functional architecture of monkey striate cortex , 1968, The Journal of physiology.

[23]  J Hirsch,et al.  Limits of spatial-frequency discrimination as evidence of neural interpolation. , 1982, Journal of the Optical Society of America.

[24]  H. Wilson,et al.  A psychophysically motivated model for two-dimensional motion perception , 1992, Visual Neuroscience.

[25]  H. Wilson,et al.  Spatial frequency tuning of orientation selective units estimated by oblique masking , 1983, Vision Research.

[26]  H. Wilson,et al.  Discrimination of contour curvature: data and theory. , 1985, Journal of the Optical Society of America. A, Optics and image science.

[27]  R. von der Heydt,et al.  Mechanisms of contour perception in monkey visual cortex. I. Lines of pattern discontinuity , 1989, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[28]  W. Richards,et al.  Mechanisms of contour curvature discrimination. , 1989, Journal of the Optical Society of America. A, Optics and image science.

[29]  D M Levi,et al.  Spatial-interval discrimination in the human fovea: what delimits the interval? , 1987, Journal of the Optical Society of America. A, Optics and image science.

[30]  H. Wilson,et al.  Modified line-element theory for spatial-frequency and width discrimination. , 1984, Journal of the Optical Society of America. A, Optics and image science.