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The number of discernible colors perceived by dichromats in natural scenes and the effects of colored lenses


The number of discernible colors perceived by normal trichromats when viewing natural scenes can be estimated by analyzing idealized color volumes or hyperspectral data obtained from actual scenes. The purpose of the present work was to estimate the relative impairment in chromatic diversity experienced by dichromats when viewing natural scenes and to investigate the effects of colored lenses. The estimates were obtained computationally from the analysis of hyperspectral images of natural scenes and using a quantitative model of dichromats' vision. The color volume corresponding to each scene was represented in CIELAB color space and segmented into cubes of unitary side. For normal trichromats, the number of discernible colors was estimated by counting the number of non-empty cubes. For dichromats, an algorithm simulating for normal observers the appearance of the scenes for dichromats was used, and the number of discernible colors was then counted as for normal trichromats. The effects of colored lenses were estimated by prior filtering the spectral radiance from the scenes with the spectral transmittance function of the lenses. It was found that in dichromatic vision the number of discernible colors was about 7% of normal trichromatic vision. With some colored lenses considerable improvements in chromatic diversity were obtained for trichromats; for dichromats, however, only modest improvements could be obtained with efficiency levels dependent on the combination of scene, lens and type of deficiency.

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Address correspondence and reprint requests to: João Manuel Maciel Linhares, Department of Physics, Minho University, Campus de Gualtar, 4710-057 Braga, Portugal. E-mail:
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H. Brettel , F. Viénot & J.D. Mollon (1997). Computerized simulation of color appearance for dichromats. Journal of the Optical Society of America A: Optics, Image Science, and Vision 14, 26472655

D.H. Foster , K. Amano , S.M.C. Nascimento & M.J. Foster (2006). Frequency of metamerism in natural scenes. Journal of the Optical Society of America A: Optics, Image Science, and Vision 23, 23592372.

D.B. Judd (1948). Color perceptions of deuteranopic and protanopic observers. Journal of Research of the National Bureau of Standards 41, 247271.

D.B. Judd & K.L. Kelly (1939). Method of designating colors. Journal of Research of the National Bureau of Standards 23, 355381.

G. Kovacs , I. Kucsera , G. Abraham & K. Wenzel (2001). Enhancing color representation for anomalous trichromats on CRT monitors. Color Research and Application 26, S273S276.

M.R. Luo , G. Cui & B. Rigg (2001). The development of the CIE 2000 colour-difference formula: CIEDE2000. Color Research and Application 26, 340350.

M.R. Luo & B. Rigg (1986). Chromaticity-discrimination ellipses for surface colors. Color Research and Application 11, 2542.

D.L. MacAdam (1947). Note on the number of distinct chromaticities. Journal of the Optical Society of America 37, 308309.

F. Martinez-Verdu , E. Perales , E. Chorro , D. de Fez , V. Viqueira & E. Gilabert (2007). Computation and visualization of the MacAdam limits for any lightness, hue angle, and light source. Journal of the Optical Society of America A: Optics, Image Science, and Vision 24, 15011515.

M.J. Morgan , A. Adam & J.D. Mollon (1992). Dichromates Detect Color-Camouflaged Objects That Are Not Detected by Trichromates. Proceedings of the Royal Society of London Series B-Biological Sciences 248, 291295.

S.M.C. Nascimento , F.P. Ferreira & D.H. Foster (2002). Statistics of spatial cone-excitation ratios in natural scenes. Journal of the Optical Society of America A: Optics, Image Science, and Vision 19, 14841490.

S.M.C. Nascimento , D.H. Foster & K. Amano (2005). Psychophysical estimates of the number of spectral-reflectance basis functions needed to reproduce natural scenes. Journal of the Optical Society of America A: Optics, Image Science, and Vision 22, 10171022.

D. Nickerson & S.M. Newhall (1943). A psychological color solid. Journal of the Optical Society of America 33, 419422.

M.R. Pointer & G.G. Attridge (1998). The number of discernible colours. Color Research and Application 23, 5254.

K. Rasche , R. Geist & J. Westall (2005). Detail preserving reproduction of color images for monochromats and dichromats. IEEE Computer Graphics and Applications 25, 2230.

A. Saito , A. Mikami , T. Hosokawa & T. Hasegawa (2006). Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans. Perceptual and Motor Skills 102, 312.

L.T. Sharpe , E. de Luca , T. Hansen , H. Jagle & K.R. Gegenfurtner (2006). Advantages and disadvantages of human dichromacy. Journal of Vision 6, 213223.

V.C. Smith & J. Pokorny (1975). Spectral sensitivity of foveal cone photopigments between 400 and 500 nm. Vision Research 15, 161171.

F. Vienot , H. Brettel & J.D. Mollon (1999). Digital video colourmaps for checking the legibility of displays by dichromats. Color Research and Application 24, 243252.

F. Vienot , H. Brettel , L. Ott , A. Benmbarek & J.D. Mollon (1995). What do color-blind people see. Nature 376, 127128.

J.J. Vos (1978). Colorimetric and photometric properties of a 2° fundamental observer. Color Research and Application 3, 125128.

T. Wachtler , U. Dohrmann & R. Hertel (2004). Modeling color percepts of dichromats. Vision Research 44, 28432855.

X. Zhang , D.A. Silverstein , J.E. Farrell & B.A. Wandell (1997). Color image quality metric S-CIELAB and its application on halftone texture visibility. In COMPCON97 Digest of Papers, pp. 4448.

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Visual Neuroscience
  • ISSN: 0952-5238
  • EISSN: 1469-8714
  • URL: /core/journals/visual-neuroscience
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