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Joao Linhares, Sergio Nascimento; Testing models of color deficiencies using normal observers with Ishihara plates simulated for color deficient observers. Journal of Vision 2010;10(7):431. doi: 10.1167/10.7.431.
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© ARVO (1962-2015); The Authors (2016-present)
The chromatic diversity of complex scenes can be simulated for normal and color deficient observers. Current models of color vision deficiencies allow to simulate for a normal observer the chromatic sensations experienced by a color deficient observers. How real such simulations are is an open question. The goal of this work was to assess the effectiveness of the simulations with normal observers viewing Ishihara plates simulated for color deficient observers. The plates were digitized with a hyperspectral imaging system and the spectral reflectance of each pixel of the plates was estimated from a gray reference surface present near the plate at the time of digitizing. Data was acquired from 400 to 720 nm in 10 nm steps. Images were assumed rendered under the D65. Simulations for normal observers of the perception of dichromatic and of anomalous color vision were done using deMarco's anomalous color matching functions (JOSA-A, 9(9): p.1465-1476, 1992) and Brettel's simulation of color appearance for dichromats (JOSA-A, 14(10): p.2647-2655, 1997). The resulting images were displayed on a calibrated 17-inch, RGB color monitor with flat screen controlled by a computer raster-graphics card providing 24 bits per pixel in true-color mode (VSG 2/5; Cambridge Research Systems, Rochester, UK). Normal observers were asked to read the numbers on the plates displayed on the screen, simulated for normal, protanomalous, deuteranomalous, protanope and deuteranope observers. Ishihara plates were displayed randomly in the same observer category to avoid plate memorization. Comparing the expected results as described in the Ishihara's test instructions with those obtained here values of about 70% to 90% were found to all observers. These results suggest that the models used describe vision of color deficient observers well enough to reproduce answers of Ishihara plates.
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