The laboratory task of effortless and immediate perceptual segregation between regions of visual texture may be a good model f an important stage in everyday visual perception -- a state at which the visual system breaks a visual scene into meaningful regions before going on to do further computations on each region. An understanding of the visual processes controlling the perceived segregation among regions may be gained by building on the vast amount of knowledge that has accrued over the last several decades about relatively low-level visual processes. Results from psychophysical experiments measuring perceived texture segregation (and several related perceptual tasks) will be collected. These empirical results will be compared to predictions from quantitative models based on current knowledge about low-level visual processes. These quantitative models will incorporate knowledge about pattern-vision analyzers (multiple analyzers acting in parallel that are selectively sensitive to spatial frequency, orientation, and spatial position -- the physiological substrate for which may be in the lowest areas of visual cortex) and also about the manifest nonlinearity studied under the name light adaptation (and probably of retinal origin) as well as some nonlinear behavior now known to be characteristic of cortical cells.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008459-02
Application #
3265781
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1989-12-01
Project End
1994-11-30
Budget Start
1990-12-01
Budget End
1991-11-30
Support Year
2
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
Other Domestic Higher Education
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10027
Graham, Norma V; Wolfson, S Sabina (2018) Is the straddle effect in contrast perception limited to second-order spatial vision? J Vis 18:15
Wolfson, S Sabina; Graham, Norma (2009) Two contrast adaptation processes: contrast normalization and shifting, rectifying contrast comparison. J Vis 9:30.1-23
Wolfson, S Sabina; Graham, Norma (2007) An unusual kind of contrast adaptation: shifting a contrast comparison level. J Vis 7:12
Wolfson, S Sabina; Graham, Norma (2006) Forty-four years of studying light adaptation using the probed-sinewave paradigm. J Vis 6:1026-46
Wolfson, S Sabina; Graham, Norma (2005) Element-arrangement textures in multiple objective tasks. Spat Vis 18:209-26
Graham, Norma; Wolfson, S Sabina (2004) Is there opponent-orientation coding in the second-order channels of pattern vision? Vision Res 44:3145-75
Wolfson, S S; Graham, N (2001) Comparing increment and decrement probes in the probed-sinewave paradigm. Vision Res 41:1119-31
Graham, N; Wolfson, S S (2001) A note about preferred orientations at the first and second stages of complex (second-order) texture channels. J Opt Soc Am A Opt Image Sci Vis 18:2273-81
Wolfson, S S; Graham, N (2001) Processing in the probed-sinewave paradigm is likely retinal. Vis Neurosci 18:1003-10
Wolfson, S S; Graham, N (2000) Exploring the dynamics of light adaptation: the effects of varying the flickering background's duration in the probed-sinewave paradigm. Vision Res 40:2277-89

Showing the most recent 10 out of 23 publications