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Independence of channels in colour contrast perception


IN the perception of brightness the responses from all three classes of cone in the human eye are pooled. Evidence from recent electrophysiological measurements1, however, indicates that the contrast detected by a particular colour channel is assessed independently of the summation. Specifically, the existence of a red sensitive channel in which this occurred was demonstrated.

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  1. 1

    Regan, D., Nature, 250, 437–439 (1974).

  2. 2

    Ellis, B., Burrell, G. J., Wharf, J. H., Hawkins, T. D. F., and Peters, D. V., Proc. Soc. Inf. Display, 15, 150–160 (1974).

  3. 3

    Ellis, B., Burrell, G. J., Wharf, J. H., and Hawkins, T. D. F., Soc. Inform. Displ. Symp. Digest, 106–107 (San Diego, 1974).

  4. 4

    Wald, G., Science, 145, 1007–1017 (1964).

  5. 5

    Rushton, W. A. H., Powell, D. S., and White, K. D., Vision Res., 13, 2003–2015 (1973).

  6. 6

    Stiles, W. S., Proc. natn. Acad. Sci. U.S.A., 45, 100–114 (1959).

  7. 7

    Tyte, R. N., Wharf, J. H., and Ellis, B., Soc. Inform. Displ. Symp. Digest (Washington, in the press).

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