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Albert J. Ahumada, Sophie M. Wuerger, Andrew B. Watson; Estimation of chromatic channel spatial frequency responses. Journal of Vision 2003;3(12):43. doi: 10.1167/3.12.43.
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© ARVO (1962-2015); The Authors (2016-present)
Wuerger, Watson, and Ahumada (2002 SPIE Proc. Vol. 4662) attempted to extend the original ModelFest (http://vision.arc.nasa.gov/modelfest/) experiments to colored images. They measured detection thresholds on three observers for the large Gabor patch stimuli modulated along different color directions for a wide range of spatial frequencies. The three main directions were an achromatic direction, a nominally isoluminant red-green direction, and the tritanopic confusion line. Here we report estimates of the contrast sensitivity functions for the three chromatic mechanisms based on these measurements. Previous attempts to estimate the sensitivities of these mechanisms were hampered by the large number of parameters being jointly estimated. For all three observers the achromatic detection spatial frequency response was very accurately predicted by a curve fit to the original Model-Fest data for the large Gabor patches, with only a single multiplicative contrast sensitivity parameter for each observer. The chromatic patch detection results were predicted by the more sensitive of a Gaussian low-pass spatial frequency response or the achromatic response function. Significantly different Gaussian spatial spread parameters were not found for the different chromatic directions.
Watson, A. B. (2000). Visual detection of spatial contrast patterns: Evaluation of five simple models, Optics Express, 6(1), 12–33.
Wuerger, S., Watson, A. B., Ahumada, A. J. Jr. (2002). Toward a standard observer for spatio-chromatic detection, Proceedings of the SPIE, 4662, 159–172.
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