Abstract

Illumination varies greatly both across parts of a natural scene and as a function of time, whereas the spectral reflectance function of surfaces remains more stable and is of much greater relevance when searching for specific targets. This study investigates the functional properties of postreceptoral opponent-channel responses, in particular regarding their stability against spatial and temporal variation in illumination. We studied images of natural scenes obtained in UK and Uganda with digital cameras calibrated to produce estimated L-, M-, and S-cone responses of trichromatic primates (human) and birds (starling). For both primates and birds we calculated luminance and red–green opponent (RG) responses. We also calculated a primate blue–yellow-opponent (BY) response. The BY response varies with changes in illumination, both across time and across the image, rendering this factor less invariant. The RG response is much more stable than the BY response across such changes in illumination for primates, less so for birds. These differences between species are due to the greater separation of bird L and M cones in wavelength and the narrower bandwidth of the cone action spectra. This greater separation also produces a larger chromatic signal for a given change in spectral reflectance. Thus bird vision seems to suffer a greater degree of spatiotemporal “clutter” than primate vision, but also enhances differences between targets and background. Therefore, there may be a trade-off between the degree of chromatic clutter in a visual system versus the degree of chromatic difference between a target and its background. Primate and bird visual systems have found different solutions to this trade-off.

© 2005 Optical Society of America

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  1. K. T. Mullen, F. A. A. Kingdom, “Colour contrast in form perception,” in The Perception of Colour, P. Gouras, ed. (Macmillan, 1991), pp. 198–217.
  2. V. V. Maximov, “Environmental factors which may have led to the appearance of colour vision,” Philos. Trans. R. Soc. London, Ser. B 355, 1239–1242 (2000).
    [CrossRef] [PubMed]
  3. R. L. De Valois, “Analysis and coding of color vision in the primate visual system,” Cold Spring Harbor Symp. Quant. Biol. 30, 567–580 (1965).
    [CrossRef] [PubMed]
  4. R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
    [CrossRef] [PubMed]
  5. R. L. De Valois, K. K. De Valois, “A multistage color model,” Vision Res. 33, 1053–1065 (1993).
    [CrossRef] [PubMed]
  6. L. M. Hurvich, D. Jameson, “An opponent-process theory of colour vision,” Psychol. Rev. 64, 384–404 (1957).
    [CrossRef]
  7. G. H. Jacobs, “Primate photopigments and primate color vision,” Proc. Natl. Acad. Sci. U.S.A. 93, 577–581 (1996).
    [CrossRef] [PubMed]
  8. T. N. Wiesel, D. H. Hubel, “Spatial and chromatic interactions in the lateral geniculate nucleous of the rhesus monkey,” J. Neurophysiol. 29, 1115–1156 (1966).
    [PubMed]
  9. F. M. De Monasterio, P. Gouras, “Functional properties of ganglion cells of the rhesus monkey retina,” J. Physiol. (London) 251, 167–195 (1975).
  10. D. L. Ruderman, T. W. Cronin, C. C. Chiao, “Statistics of cone responses to natural images: implications for visual coding,” J. Opt. Soc. Am. A 15, 2036–2045 (1998).
    [CrossRef]
  11. J. D. Mollon, ““Tho she kneeld in that place where they grew.” The uses and origins of primate colour vision,” J. Exp. Biol. 146, 21–38 (1989).
    [PubMed]
  12. G. D. Finlayson, S. D. Hordley, “Color constancy at a pixel,” J. Opt. Soc. Am. A 18, 253–264 (2001).
    [CrossRef]
  13. C. C. Chiao, D. Osorio, M. Vorobyev, T. W. Cronin, “Characterization of natural illuminants in forests and the use of digital video data to reconstruct illuminant spectra,” J. Opt. Soc. Am. A 17, 1713–1721 (2000).
    [CrossRef]
  14. T. Troscianko, J. P. Harris, “Phase discrimination in chromatic gratings,” Perception 15, A18 (1986).
  15. D. Steverding, T. Troscianko, “On the role of blue shadows in the visual behaviour of tsetse flies,” Proc. R. Soc. London, Ser. B 271, S16–S17 (2003).
    [CrossRef]
  16. A. Olmos, F. A. A. Kingdom, “A biologically inspired algorithm for the recovery of shading and reflectance images,” Perception 33, 1463–1473 (2004).
    [CrossRef]
  17. M. G. Nagle, D. Osorio, “The tuning of human photopigments may minimize red-green chromatic signals in natural conditions,” Proc. R. Soc. London, Ser. B 252, 209–213 (1993).
    [CrossRef]
  18. P. Sumner, J. D. Mollon, “Catarrhine photopigments are optimized for detecting targets against a foliage background,” J. Exp. Biol. 203, 1963–1986 (2000).
    [PubMed]
  19. N. J. Dominy, P. W. Lucas, “Ecological importance of trichromatic vision to primates,” Nature (London) 410, 363–365 (2001).
    [CrossRef]
  20. B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
    [CrossRef] [PubMed]
  21. C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
    [CrossRef] [PubMed]
  22. N. S. Hart, J. C. Partridge, I. C. Cuthill, “Visual pigments, oil droplets and cone photoreceptor distribution in the European starling (Sturnus vulgaris),” J. Exp. Biol. 201, 1433–1446 (1998).
    [PubMed]
  23. D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
    [PubMed]
  24. C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).
  25. T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
    [CrossRef]
  26. T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).
  27. V. C. Smith, J. Pokorny, “Spectral sensitivity of color-blind observers and the cone photopigments,” Vision Res. 12, 2059–2071 (1972).
    [CrossRef] [PubMed]
  28. V. C. Smith, J. Pokorny, “Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm,” Vision Res. 15, 161–171 (1975).
    [CrossRef] [PubMed]
  29. J. A. Endler, “The color of light in forests and its implications,” Ecol. Monogr. 63, 1–27 (1993).
    [CrossRef]
  30. L. T. Maloney, B. A. Wandell, “Color constancy: a method for recovering surface spectral reflectance,” J. Opt. Soc. Am. A 3, 29–33 (1986).
    [CrossRef] [PubMed]
  31. W. S. Stiles, G. Wyszecki, N. Ohta, “Counting metameric object-colour stimuli using frequency-limited spectral reflectance functions,” J. Opt. Soc. Am. 67, 779–784 (1977).
    [CrossRef]
  32. L. T. Maloney, “Evaluation of linear models of surface spectral reflectance with small numbers of parameters,” J. Opt. Soc. Am. A 3, 1673–1683 (1986).
    [CrossRef] [PubMed]
  33. J. L. Dannemiller, “Spectral reflectance of natural objects: how many basis functions are necessary?” J. Opt. Soc. Am. A 9, 507–515 (1992).
    [CrossRef]
  34. D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).
  35. E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).
  36. V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).
  37. D. Connah, S. Westland, M. G. A. Thomson, “Recovering spectral information using digital camera systems,” Coloration Technol. 117, 309–311 (2001).
  38. G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
    [CrossRef]
  39. T. Johnson, “Methods for characterising colour scanners and digital cameras,” Displays 16, 183–191 (1996).
    [CrossRef]
  40. M. Shi, G. Healey, “Using reflectance models for color scanner calibration,” J. Opt. Soc. Am. A 19, 645–656 (2002).
    [CrossRef]
  41. S. Westland, C. Ripamonti, Computational Color Science Using Matlab (Wiley, 2004).
    [CrossRef]
  42. J. Parkkinen, T. Jaaskelainen, M. Kuittinen, “Spectral representation of color images,” presented at the IEEE 9th International Conference on Pattern Recognition, Rome, Italy, November 14–17, 1988.
  43. G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, 1967), pp. xiv, 628.
  44. P. Sumner, B. C. Regan, J. D. Mollon, “Cambridge database of natural spectra” (2004); http://vision.psychol.cam.ac.uk/spectra/.
  45. D. I. A. MacLeod, R. M. Boynton, “Chromaticity diagram showing cone excitation by stimuli of equal luminance,” J. Opt. Soc. Am. 68, 1183–1187 (1979).
    [CrossRef]
  46. C. A. Párraga, G. Brelstaff, T. Troscianko, I. R. Moorhead, “Color and luminance information in natural scenes,” J. Opt. Soc. Am. A 15, 563–569 (1998).
    [CrossRef]
  47. C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
    [CrossRef]
  48. M. Vorobyev, m.vorobyev@uq.edu.au (personal communication, 2005).
  49. A. Gilchrist, “Perceived lightness depends on perceived spatial arrangement,” Science 195, 185–187 (1977).
    [CrossRef] [PubMed]
  50. A. Gilchrist, V. Annan, “Articulation effects in lightness: historical background and theoretical implications,” Perception 31, 141–150 (2002).
    [CrossRef] [PubMed]
  51. A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
    [CrossRef] [PubMed]

2004 (2)

A. Olmos, F. A. A. Kingdom, “A biologically inspired algorithm for the recovery of shading and reflectance images,” Perception 33, 1463–1473 (2004).
[CrossRef]

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

2003 (4)

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

D. Steverding, T. Troscianko, “On the role of blue shadows in the visual behaviour of tsetse flies,” Proc. R. Soc. London, Ser. B 271, S16–S17 (2003).
[CrossRef]

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

2002 (4)

A. Gilchrist, V. Annan, “Articulation effects in lightness: historical background and theoretical implications,” Perception 31, 141–150 (2002).
[CrossRef] [PubMed]

M. Shi, G. Healey, “Using reflectance models for color scanner calibration,” J. Opt. Soc. Am. A 19, 645–656 (2002).
[CrossRef]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
[CrossRef] [PubMed]

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

2001 (5)

N. J. Dominy, P. W. Lucas, “Ecological importance of trichromatic vision to primates,” Nature (London) 410, 363–365 (2001).
[CrossRef]

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

G. D. Finlayson, S. D. Hordley, “Color constancy at a pixel,” J. Opt. Soc. Am. A 18, 253–264 (2001).
[CrossRef]

D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).

C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
[CrossRef]

2000 (4)

C. C. Chiao, D. Osorio, M. Vorobyev, T. W. Cronin, “Characterization of natural illuminants in forests and the use of digital video data to reconstruct illuminant spectra,” J. Opt. Soc. Am. A 17, 1713–1721 (2000).
[CrossRef]

P. Sumner, J. D. Mollon, “Catarrhine photopigments are optimized for detecting targets against a foliage background,” J. Exp. Biol. 203, 1963–1986 (2000).
[PubMed]

V. V. Maximov, “Environmental factors which may have led to the appearance of colour vision,” Philos. Trans. R. Soc. London, Ser. B 355, 1239–1242 (2000).
[CrossRef] [PubMed]

G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
[CrossRef]

1999 (1)

D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
[PubMed]

1998 (3)

1996 (2)

G. H. Jacobs, “Primate photopigments and primate color vision,” Proc. Natl. Acad. Sci. U.S.A. 93, 577–581 (1996).
[CrossRef] [PubMed]

T. Johnson, “Methods for characterising colour scanners and digital cameras,” Displays 16, 183–191 (1996).
[CrossRef]

1993 (3)

J. A. Endler, “The color of light in forests and its implications,” Ecol. Monogr. 63, 1–27 (1993).
[CrossRef]

R. L. De Valois, K. K. De Valois, “A multistage color model,” Vision Res. 33, 1053–1065 (1993).
[CrossRef] [PubMed]

M. G. Nagle, D. Osorio, “The tuning of human photopigments may minimize red-green chromatic signals in natural conditions,” Proc. R. Soc. London, Ser. B 252, 209–213 (1993).
[CrossRef]

1992 (1)

1989 (1)

J. D. Mollon, ““Tho she kneeld in that place where they grew.” The uses and origins of primate colour vision,” J. Exp. Biol. 146, 21–38 (1989).
[PubMed]

1986 (3)

1979 (1)

D. I. A. MacLeod, R. M. Boynton, “Chromaticity diagram showing cone excitation by stimuli of equal luminance,” J. Opt. Soc. Am. 68, 1183–1187 (1979).
[CrossRef]

1977 (2)

1975 (2)

V. C. Smith, J. Pokorny, “Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm,” Vision Res. 15, 161–171 (1975).
[CrossRef] [PubMed]

F. M. De Monasterio, P. Gouras, “Functional properties of ganglion cells of the rhesus monkey retina,” J. Physiol. (London) 251, 167–195 (1975).

1972 (1)

V. C. Smith, J. Pokorny, “Spectral sensitivity of color-blind observers and the cone photopigments,” Vision Res. 12, 2059–2071 (1972).
[CrossRef] [PubMed]

1966 (2)

R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

T. N. Wiesel, D. H. Hubel, “Spatial and chromatic interactions in the lateral geniculate nucleous of the rhesus monkey,” J. Neurophysiol. 29, 1115–1156 (1966).
[PubMed]

1965 (1)

R. L. De Valois, “Analysis and coding of color vision in the primate visual system,” Cold Spring Harbor Symp. Quant. Biol. 30, 567–580 (1965).
[CrossRef] [PubMed]

1957 (1)

L. M. Hurvich, D. Jameson, “An opponent-process theory of colour vision,” Psychol. Rev. 64, 384–404 (1957).
[CrossRef]

Abramov, I.

Amano, K.

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).

Annan, V.

A. Gilchrist, V. Annan, “Articulation effects in lightness: historical background and theoretical implications,” Perception 31, 141–150 (2002).
[CrossRef] [PubMed]

Baddeley, R. J.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

Boynton, R. M.

D. I. A. MacLeod, R. M. Boynton, “Chromaticity diagram showing cone excitation by stimuli of equal luminance,” J. Opt. Soc. Am. 68, 1183–1187 (1979).
[CrossRef]

Brelstaff, G.

Buchanan-Smith, H. M.

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

Charles-Dominique, P.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

Cheung, V.

V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).

Chiao, C. C.

Connah, D.

D. Connah, S. Westland, M. G. A. Thomson, “Recovering spectral information using digital camera systems,” Coloration Technol. 117, 309–311 (2001).

V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).

Cronin, T. W.

Cuthill, I. C.

N. S. Hart, J. C. Partridge, I. C. Cuthill, “Visual pigments, oil droplets and cone photoreceptor distribution in the European starling (Sturnus vulgaris),” J. Exp. Biol. 201, 1433–1446 (1998).
[PubMed]

Dannemiller, J. L.

De Monasterio, F. M.

F. M. De Monasterio, P. Gouras, “Functional properties of ganglion cells of the rhesus monkey retina,” J. Physiol. (London) 251, 167–195 (1975).

De Valois, K. K.

R. L. De Valois, K. K. De Valois, “A multistage color model,” Vision Res. 33, 1053–1065 (1993).
[CrossRef] [PubMed]

De Valois, R. L.

R. L. De Valois, K. K. De Valois, “A multistage color model,” Vision Res. 33, 1053–1065 (1993).
[CrossRef] [PubMed]

R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

R. L. De Valois, “Analysis and coding of color vision in the primate visual system,” Cold Spring Harbor Symp. Quant. Biol. 30, 567–580 (1965).
[CrossRef] [PubMed]

Dominy, N. J.

N. J. Dominy, P. W. Lucas, “Ecological importance of trichromatic vision to primates,” Nature (London) 410, 363–365 (2001).
[CrossRef]

Endler, J. A.

J. A. Endler, “The color of light in forests and its implications,” Ecol. Monogr. 63, 1–27 (1993).
[CrossRef]

Finlayson, G. D.

Foster, D. H.

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).

Gilchrist, A.

A. Gilchrist, V. Annan, “Articulation effects in lightness: historical background and theoretical implications,” Perception 31, 141–150 (2002).
[CrossRef] [PubMed]

A. Gilchrist, “Perceived lightness depends on perceived spatial arrangement,” Science 195, 185–187 (1977).
[CrossRef] [PubMed]

Gouras, P.

F. M. De Monasterio, P. Gouras, “Functional properties of ganglion cells of the rhesus monkey retina,” J. Physiol. (London) 251, 167–195 (1975).

Harris, J. P.

T. Troscianko, J. P. Harris, “Phase discrimination in chromatic gratings,” Perception 15, A18 (1986).

Hart, N. S.

N. S. Hart, J. C. Partridge, I. C. Cuthill, “Visual pigments, oil droplets and cone photoreceptor distribution in the European starling (Sturnus vulgaris),” J. Exp. Biol. 201, 1433–1446 (1998).
[PubMed]

Healey, G.

Hong, G.

G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
[CrossRef]

Hordley, S. D.

Hubel, D. H.

T. N. Wiesel, D. H. Hubel, “Spatial and chromatic interactions in the lateral geniculate nucleous of the rhesus monkey,” J. Neurophysiol. 29, 1115–1156 (1966).
[PubMed]

Hurvich, L. M.

L. M. Hurvich, D. Jameson, “An opponent-process theory of colour vision,” Psychol. Rev. 64, 384–404 (1957).
[CrossRef]

Jaaskelainen, T.

J. Parkkinen, T. Jaaskelainen, M. Kuittinen, “Spectral representation of color images,” presented at the IEEE 9th International Conference on Pattern Recognition, Rome, Italy, November 14–17, 1988.

Jacobs, G. H.

G. H. Jacobs, “Primate photopigments and primate color vision,” Proc. Natl. Acad. Sci. U.S.A. 93, 577–581 (1996).
[CrossRef] [PubMed]

R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

Jameson, D.

L. M. Hurvich, D. Jameson, “An opponent-process theory of colour vision,” Psychol. Rev. 64, 384–404 (1957).
[CrossRef]

Johnson, T.

T. Johnson, “Methods for characterising colour scanners and digital cameras,” Displays 16, 183–191 (1996).
[CrossRef]

Jones, C. D.

D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
[PubMed]

Julliot, C.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

Kingdom, F. A. A.

A. Olmos, F. A. A. Kingdom, “A biologically inspired algorithm for the recovery of shading and reflectance images,” Perception 33, 1463–1473 (2004).
[CrossRef]

K. T. Mullen, F. A. A. Kingdom, “Colour contrast in form perception,” in The Perception of Colour, P. Gouras, ed. (Macmillan, 1991), pp. 198–217.

Kuittinen, M.

J. Parkkinen, T. Jaaskelainen, M. Kuittinen, “Spectral representation of color images,” presented at the IEEE 9th International Conference on Pattern Recognition, Rome, Italy, November 14–17, 1988.

Leonards, U.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

Lovell, P. G.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

Lucas, P. W.

N. J. Dominy, P. W. Lucas, “Ecological importance of trichromatic vision to primates,” Nature (London) 410, 363–365 (2001).
[CrossRef]

Luo, M. R.

G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
[CrossRef]

MacLeod, D. I. A.

D. I. A. MacLeod, R. M. Boynton, “Chromaticity diagram showing cone excitation by stimuli of equal luminance,” J. Opt. Soc. Am. 68, 1183–1187 (1979).
[CrossRef]

Maloney, L. T.

Maximov, V. V.

V. V. Maximov, “Environmental factors which may have led to the appearance of colour vision,” Philos. Trans. R. Soc. London, Ser. B 355, 1239–1242 (2000).
[CrossRef] [PubMed]

Mollon, J. D.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

P. Sumner, J. D. Mollon, “Catarrhine photopigments are optimized for detecting targets against a foliage background,” J. Exp. Biol. 203, 1963–1986 (2000).
[PubMed]

J. D. Mollon, ““Tho she kneeld in that place where they grew.” The uses and origins of primate colour vision,” J. Exp. Biol. 146, 21–38 (1989).
[PubMed]

P. Sumner, B. C. Regan, J. D. Mollon, “Cambridge database of natural spectra” (2004); http://vision.psychol.cam.ac.uk/spectra/.

Moorhead, I. R.

Mullen, K. T.

K. T. Mullen, F. A. A. Kingdom, “Colour contrast in form perception,” in The Perception of Colour, P. Gouras, ed. (Macmillan, 1991), pp. 198–217.

Mundy, N. I.

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

Nagle, M. G.

M. G. Nagle, D. Osorio, “The tuning of human photopigments may minimize red-green chromatic signals in natural conditions,” Proc. R. Soc. London, Ser. B 252, 209–213 (1993).
[CrossRef]

Nascimento, S. M. C.

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).

Ohta, N.

Olmos, A.

A. Olmos, F. A. A. Kingdom, “A biologically inspired algorithm for the recovery of shading and reflectance images,” Perception 33, 1463–1473 (2004).
[CrossRef]

Osorio, D.

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

C. C. Chiao, D. Osorio, M. Vorobyev, T. W. Cronin, “Characterization of natural illuminants in forests and the use of digital video data to reconstruct illuminant spectra,” J. Opt. Soc. Am. A 17, 1713–1721 (2000).
[CrossRef]

D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
[PubMed]

M. G. Nagle, D. Osorio, “The tuning of human photopigments may minimize red-green chromatic signals in natural conditions,” Proc. R. Soc. London, Ser. B 252, 209–213 (1993).
[CrossRef]

Oxtoby, E. K.

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

Parkkinen, J.

J. Parkkinen, T. Jaaskelainen, M. Kuittinen, “Spectral representation of color images,” presented at the IEEE 9th International Conference on Pattern Recognition, Rome, Italy, November 14–17, 1988.

Párraga, C. A.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
[CrossRef] [PubMed]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
[CrossRef]

C. A. Párraga, G. Brelstaff, T. Troscianko, I. R. Moorhead, “Color and luminance information in natural scenes,” J. Opt. Soc. Am. A 15, 563–569 (1998).
[CrossRef]

Partridge, J. C.

N. S. Hart, J. C. Partridge, I. C. Cuthill, “Visual pigments, oil droplets and cone photoreceptor distribution in the European starling (Sturnus vulgaris),” J. Exp. Biol. 201, 1433–1446 (1998).
[PubMed]

Pokorny, J.

V. C. Smith, J. Pokorny, “Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm,” Vision Res. 15, 161–171 (1975).
[CrossRef] [PubMed]

V. C. Smith, J. Pokorny, “Spectral sensitivity of color-blind observers and the cone photopigments,” Vision Res. 12, 2059–2071 (1972).
[CrossRef] [PubMed]

Regan, B. C.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

P. Sumner, B. C. Regan, J. D. Mollon, “Cambridge database of natural spectra” (2004); http://vision.psychol.cam.ac.uk/spectra/.

Rhodes, P. A.

G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
[CrossRef]

Ripamonti, C.

S. Westland, C. Ripamonti, Computational Color Science Using Matlab (Wiley, 2004).
[CrossRef]

V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).

Ruderman, D. L.

Shi, M.

Simmen, B.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

Smith, A. C.

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

Smith, V. C.

V. C. Smith, J. Pokorny, “Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm,” Vision Res. 15, 161–171 (1975).
[CrossRef] [PubMed]

V. C. Smith, J. Pokorny, “Spectral sensitivity of color-blind observers and the cone photopigments,” Vision Res. 12, 2059–2071 (1972).
[CrossRef] [PubMed]

Steverding, D.

D. Steverding, T. Troscianko, “On the role of blue shadows in the visual behaviour of tsetse flies,” Proc. R. Soc. London, Ser. B 271, S16–S17 (2003).
[CrossRef]

Stiles, W. S.

W. S. Stiles, G. Wyszecki, N. Ohta, “Counting metameric object-colour stimuli using frequency-limited spectral reflectance functions,” J. Opt. Soc. Am. 67, 779–784 (1977).
[CrossRef]

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, 1967), pp. xiv, 628.

Sumner, P.

P. Sumner, J. D. Mollon, “Catarrhine photopigments are optimized for detecting targets against a foliage background,” J. Exp. Biol. 203, 1963–1986 (2000).
[PubMed]

P. Sumner, B. C. Regan, J. D. Mollon, “Cambridge database of natural spectra” (2004); http://vision.psychol.cam.ac.uk/spectra/.

Surridge, A. K.

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

Thomson, M. G. A.

D. Connah, S. Westland, M. G. A. Thomson, “Recovering spectral information using digital camera systems,” Coloration Technol. 117, 309–311 (2001).

Tolhurst, D. J.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
[CrossRef] [PubMed]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
[CrossRef]

Troscianko, J.

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

Troscianko, T.

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).

D. Steverding, T. Troscianko, “On the role of blue shadows in the visual behaviour of tsetse flies,” Proc. R. Soc. London, Ser. B 271, S16–S17 (2003).
[CrossRef]

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
[CrossRef] [PubMed]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
[CrossRef]

C. A. Párraga, G. Brelstaff, T. Troscianko, I. R. Moorhead, “Color and luminance information in natural scenes,” J. Opt. Soc. Am. A 15, 563–569 (1998).
[CrossRef]

T. Troscianko, J. P. Harris, “Phase discrimination in chromatic gratings,” Perception 15, A18 (1986).

Vienot, F.

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

Vorobyev, M.

C. C. Chiao, D. Osorio, M. Vorobyev, T. W. Cronin, “Characterization of natural illuminants in forests and the use of digital video data to reconstruct illuminant spectra,” J. Opt. Soc. Am. A 17, 1713–1721 (2000).
[CrossRef]

D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
[PubMed]

M. Vorobyev, m.vorobyev@uq.edu.au (personal communication, 2005).

Wandell, B. A.

Westland, S.

V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).

S. Westland, C. Ripamonti, Computational Color Science Using Matlab (Wiley, 2004).
[CrossRef]

D. Connah, S. Westland, M. G. A. Thomson, “Recovering spectral information using digital camera systems,” Coloration Technol. 117, 309–311 (2001).

Wiesel, T. N.

T. N. Wiesel, D. H. Hubel, “Spatial and chromatic interactions in the lateral geniculate nucleous of the rhesus monkey,” J. Neurophysiol. 29, 1115–1156 (1966).
[PubMed]

Wyszecki, G.

W. S. Stiles, G. Wyszecki, N. Ohta, “Counting metameric object-colour stimuli using frequency-limited spectral reflectance functions,” J. Opt. Soc. Am. 67, 779–784 (1977).
[CrossRef]

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, 1967), pp. xiv, 628.

Cold Spring Harbor Symp. Quant. Biol. (1)

R. L. De Valois, “Analysis and coding of color vision in the primate visual system,” Cold Spring Harbor Symp. Quant. Biol. 30, 567–580 (1965).
[CrossRef] [PubMed]

Color Res. Appl. (1)

G. Hong, M. R. Luo, P. A. Rhodes, “A study of digital camera colorimetric characterization based on polynomial modeling,” Color Res. Appl. 26, 76–84 (2000).
[CrossRef]

Curr. Biol. (2)

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Spatiochromatic properties of natural images and human vision,” Curr. Biol. 12, 483–487 (2002).
[CrossRef] [PubMed]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, (2000). “The human visual system is optimised for processing the spatial information in natural visual images,” Curr. Biol. 10, 35–38 (2001).
[CrossRef]

Displays (1)

T. Johnson, “Methods for characterising colour scanners and digital cameras,” Displays 16, 183–191 (1996).
[CrossRef]

Ecol. Monogr. (1)

J. A. Endler, “The color of light in forests and its implications,” Ecol. Monogr. 63, 1–27 (1993).
[CrossRef]

Invest. Ophthalmol. Visual Sci. (1)

D. H. Foster, K. Amano, S. M. C. Nascimento, “Color anisotropy for detecting violations of color constancy in natural scenes under daylight changes,” Invest. Ophthalmol. Visual Sci. 42, Suppl., S720 (2001).

J. Exp. Biol. (5)

J. D. Mollon, ““Tho she kneeld in that place where they grew.” The uses and origins of primate colour vision,” J. Exp. Biol. 146, 21–38 (1989).
[PubMed]

P. Sumner, J. D. Mollon, “Catarrhine photopigments are optimized for detecting targets against a foliage background,” J. Exp. Biol. 203, 1963–1986 (2000).
[PubMed]

N. S. Hart, J. C. Partridge, I. C. Cuthill, “Visual pigments, oil droplets and cone photoreceptor distribution in the European starling (Sturnus vulgaris),” J. Exp. Biol. 201, 1433–1446 (1998).
[PubMed]

D. Osorio, M. Vorobyev, C. D. Jones, “Colour vision of domestic chicks,” J. Exp. Biol. 202, 2951–2959 (1999).
[PubMed]

A. C. Smith, H. M. Buchanan-Smith, A. K. Surridge, D. Osorio, N. I. Mundy, “The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.),” J. Exp. Biol. 206, 3159–3165 (2003).
[CrossRef] [PubMed]

J. Neurophysiol. (1)

T. N. Wiesel, D. H. Hubel, “Spatial and chromatic interactions in the lateral geniculate nucleous of the rhesus monkey,” J. Neurophysiol. 29, 1115–1156 (1966).
[PubMed]

J. Opt. Soc. Am. (3)

J. Opt. Soc. Am. A (8)

J. Physiol. (London) (1)

F. M. De Monasterio, P. Gouras, “Functional properties of ganglion cells of the rhesus monkey retina,” J. Physiol. (London) 251, 167–195 (1975).

Nature (London) (1)

N. J. Dominy, P. W. Lucas, “Ecological importance of trichromatic vision to primates,” Nature (London) 410, 363–365 (2001).
[CrossRef]

Perception (7)

T. Troscianko, J. P. Harris, “Phase discrimination in chromatic gratings,” Perception 15, A18 (1986).

A. Olmos, F. A. A. Kingdom, “A biologically inspired algorithm for the recovery of shading and reflectance images,” Perception 33, 1463–1473 (2004).
[CrossRef]

C. A. Párraga, T. Troscianko, D. J. Tolhurst, “Performing a naturalistic visual task when the spatial structure of colour in natural scenes is changed,” Perception 32, Suppl., 168 (2003).

T. Troscianko, C. A. Párraga, U. Leonards, R. J. Baddeley, J. Troscianko, D. J. Tolhurst, “Leaves, fruit, shadows, and lighting in Kibale Forest, Uganda,” Perception 32, Suppl., 51 (2003).
[CrossRef]

T. Troscianko, C. A. Párraga, P. G. Lovell, D. J. Tolhurst, R. J. Baddeley, U. Leonards, “Natural illumination, shadows and primate colour vision,” Perception 33, Suppl., 45A (2004).

E. K. Oxtoby, D. H. Foster, K. Amano, S. M. C. Nascimento, “How many basis functions are needed to reproduce coloured patterns under illuminant changes?” Perception 31, Suppl., 66 (2002).

A. Gilchrist, V. Annan, “Articulation effects in lightness: historical background and theoretical implications,” Perception 31, 141–150 (2002).
[CrossRef] [PubMed]

Philos. Trans. R. Soc. London, Ser. B (2)

V. V. Maximov, “Environmental factors which may have led to the appearance of colour vision,” Philos. Trans. R. Soc. London, Ser. B 355, 1239–1242 (2000).
[CrossRef] [PubMed]

B. C. Regan, C. Julliot, B. Simmen, F. Vienot, P. Charles-Dominique, J. D. Mollon, “Fruits, foliage and the evolution of primate colour vision,” Philos. Trans. R. Soc. London, Ser. B 356, 229–284 (2001).
[CrossRef] [PubMed]

Proc. Natl. Acad. Sci. U.S.A. (1)

G. H. Jacobs, “Primate photopigments and primate color vision,” Proc. Natl. Acad. Sci. U.S.A. 93, 577–581 (1996).
[CrossRef] [PubMed]

Proc. R. Soc. London, Ser. B (2)

M. G. Nagle, D. Osorio, “The tuning of human photopigments may minimize red-green chromatic signals in natural conditions,” Proc. R. Soc. London, Ser. B 252, 209–213 (1993).
[CrossRef]

D. Steverding, T. Troscianko, “On the role of blue shadows in the visual behaviour of tsetse flies,” Proc. R. Soc. London, Ser. B 271, S16–S17 (2003).
[CrossRef]

Psychol. Rev. (1)

L. M. Hurvich, D. Jameson, “An opponent-process theory of colour vision,” Psychol. Rev. 64, 384–404 (1957).
[CrossRef]

Science (1)

A. Gilchrist, “Perceived lightness depends on perceived spatial arrangement,” Science 195, 185–187 (1977).
[CrossRef] [PubMed]

Vision Res. (3)

R. L. De Valois, K. K. De Valois, “A multistage color model,” Vision Res. 33, 1053–1065 (1993).
[CrossRef] [PubMed]

V. C. Smith, J. Pokorny, “Spectral sensitivity of color-blind observers and the cone photopigments,” Vision Res. 12, 2059–2071 (1972).
[CrossRef] [PubMed]

V. C. Smith, J. Pokorny, “Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm,” Vision Res. 15, 161–171 (1975).
[CrossRef] [PubMed]

Other (8)

K. T. Mullen, F. A. A. Kingdom, “Colour contrast in form perception,” in The Perception of Colour, P. Gouras, ed. (Macmillan, 1991), pp. 198–217.

V. Cheung, S. Westland, D. Connah, C. Ripamonti, “A comparative study of the characterisation of colour cameras by means of neural networks and polynomial transforms,” Coloration Technol. 120, 19–25 (2004).

D. Connah, S. Westland, M. G. A. Thomson, “Recovering spectral information using digital camera systems,” Coloration Technol. 117, 309–311 (2001).

S. Westland, C. Ripamonti, Computational Color Science Using Matlab (Wiley, 2004).
[CrossRef]

J. Parkkinen, T. Jaaskelainen, M. Kuittinen, “Spectral representation of color images,” presented at the IEEE 9th International Conference on Pattern Recognition, Rome, Italy, November 14–17, 1988.

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulas (Wiley, 1967), pp. xiv, 628.

P. Sumner, B. C. Regan, J. D. Mollon, “Cambridge database of natural spectra” (2004); http://vision.psychol.cam.ac.uk/spectra/.

M. Vorobyev, m.vorobyev@uq.edu.au (personal communication, 2005).

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Figures (8)

Fig. 1
Fig. 1

(Color online) This montage shows examples of the digitized color photographs that we analyze in this paper. Photograph A features ripe and unripe tomatoes; the opponent responses to tomatoes x, y, and z are examined later. Note that x is shadowed while y and z are illuminated by direct sunlight. Photographs B and C are examples of the 113 photographs of ripe fruit taken from the Kibale dataset. Photograph D is one of a time-lapse sequence taken at 4 min intervals from dawn till dusk; note the gray card in upper left, which was used to take radiometric measurements of the illuminant. These images are the regular output of the cameras; they have not been linearized or gamma corrected for display. In D, thin blue lines outline one or more fruits whose pixels were compared with the surrounding area defined by the thin red lines.

Fig. 2
Fig. 2

(A) Cone sensitivities for humans, scaled to unity. (B) Cone sensitivities for the selected starling cones. Note that the L and M cones are much closer to one another for humans than they are in the case of the starling. The bandwidths of the L and M cones also differ; they are narrower for the starling.

Fig. 3
Fig. 3

Top row, gray-level representations of the activation in the primate (A) RG- and (B) BY opponent channels calculated for the image of tomatoes in Fig. 1(A). Middle row, histograms of pixel activity levels for the ripe fruit (x, y, z) and the area surrounding each fruit; note the largely separate distributions for fruit (black curves) and the surround (gray curves) in the RG channel [plot (C)]. In the BY channel the distribution for the shadowed fruit (x) is similar to that of its surround [plot (D)]. Bottom row, d values for each ripe-fruit region compared with its surrounding (nonripe fruit and leaves) area in the RG channel [(plot E)] and the BY channel [(plot F)].

Fig. 4
Fig. 4

Summary of spectral radiance measures of sunlight during the day November 23, 2004, in a British garden (Fig. 1(D)); time zero was 07:50 GMT. (A) Plots of the normalized spectra at T1 and T2; these times are indicated as vertical lines on (B). The average of the normalized spectra is also shown. (B), The primate RG (solid curve) and By (dotted curve) chromatic opponent signals [Eqs. (8, 9)] of the light reflected from the gray card are plotted against time. The starling RG signal is also plotted (dotted–dashed) curve.

Fig. 5
Fig. 5

Plots (A) and (B) show the d values for the RG and BY signals, respectively, for a tomato in Fig. 1(D) and for a plum as a function of the time of day. The d values for both fruit are very stable in the RG opponent system despite the changes in illuminant (see Fig. 4) during the day. The d values for the plum in the BY system are also surprisingly stable. Plot C shows the actual BY signals generated from the plum, the tomato, and their leafy surrounds during the day. The BY signals do vary considerably (consistent with Fig. 4), but the signals from plum and leafy surround co-vary, so that the d value stays fairly constant.

Fig. 6
Fig. 6

(A) Averaged d scores for each fruit versus the surrounding area in the Lum channel. (B) shows the mean d scores for each fruit and surround region, i.e., the leftmost black bar shows the average of the topmost trace in Fig. 5. (C) d scores for the primate BY channel. Note the y scale for the Lum channel is an order of magnitude smaller than for the RG and BY channels. The error bars represent the standard deviations of the d scores. Solid bars are for primate channels; open bars for starling channels.

Fig. 7
Fig. 7

113 photographs of fruits in the Kibale Forest (Uganda) were analyzed as in Fig. 3. The values of the three opponent channels for both human and starling were measured for all the pixels within a ROI comprising the outline of a ripe fruit, and were compared with the values in a region of the leafy background surrounding the fruit. The bar charts show the mean d scores for (A) the luminance signal, (B) the RG opponent signal, and (C) the BY opponent signal. Solid bars are for primate opponent systems; open bars in A and B are for putative starling systems. Note that the y scale for the Lum channel bars is an order of magnitude smaller than for the BY and RG bars.

Fig. 8
Fig. 8

Time-lapse photographs were reanalyzed as in Fig. 3 while varying the position of the L cone and the bandwidth of the L and M cones. The d scores represent the mean d score for all fruit and region pairings over all time intervals. The symbols show how the difference in d scores reported for starlings and primates is due to the distance between the cones and the bandwidth of their action spectra.

Equations (11)

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L = λ l ( λ ) * Q ( λ ) * I ( λ ) , M = λ m ( λ ) * Q ( λ ) * I ( λ ) ,
S = λ s ( λ ) * Q ( λ ) * I ( λ ) ,
R = λ r ( λ ) * Q ( λ ) * I ( λ ) , G = λ g ( λ ) * Q ( λ ) * I ( λ ) ,
B = λ b ( λ ) * Q ( λ ) * I ( λ ) ,
Err = ( L L ̂ ) 2 + ( M M ̂ ) 2 + ( S S ̂ ) 2 min ( L 2 + M 2 + S 2 , L ̂ 2 + M ̂ 2 + S ̂ 2 ) ,
Lum = L + M ,
RG = L Lum ,
BY = S Lum .
RG = ( L M ) Lum .
n = s * exp ( y ) ,
d = 2 x y σ 2 ( x ) + σ 2 ( y ) .

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