Model of visual contrast gain control and pattern masking

We have implemented a model of contrast gain control in human vision that incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a divisive inhibitory gain control pool. The parameters of this model have been optimized through a fit to the recent data that describe masking of a Gabor function by cosine and Gabor masks [J. M. Foley, ''Human luminance pattern mechanisms: masking experiments require a new model,'' J. Opt. Sec. Am. A 11, 1710 (1994)]. The model achieves a good fit to the data. We also demonstrate how the concept of recruitment may accommodate a variant of this model in which excitatory and inhibitory paths have a common accelerating nonlinearity, but which include multiple channels tuned to different levels of contrast [P. C. Teo and D. J. Heeger, ''Perceptual image distortion,'' in Human Vision, Visual Processing, and Digital Display V, B. E. Rogowitz and J. P. Allebach, eds., Proc. SPIE 2179, 127 (1994)]. (C) 1997 Optical Society of America.