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. 2022 Jul 5;119(27):e2206437119.
doi: 10.1073/pnas.2206437119. Epub 2022 Jun 23.

Proximity matters

David H Brainard  1
Affiliations

Proximity matters

David H Brainard. Proc Natl Acad Sci U S A. .
No abstract available

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Conflict of interest statement

The author declares no competing interest.

Figures

Fig. 1.
Fig. 1.
(Left) The plot shows the spectral radiance of two different spectra that appear the same to a standard human observer. These two spectra map to the same point in the CIE XYZ tristimulus color space (red circle in Right). The three coordinates in this space give the intensities of three theoretical primaries required to match either of these spectra. (Center) Another pair of spectral radiances that match for a standard human observer. These two spectra are represented by the blue point in the tristimulus space in Right. (Right) Each point in the CIE tristimulus space represents a set of spectral radiances that appear the same to a human observer. The matches themselves, however, do not tell us about the perceptual distance between points, indicated by the question mark. A local metric around each point in the color space, referred to as a line element, can be created. For example, threshold measurements may be used to define a small ellipsoid around each point such that stimuli represented on the surface of the ellipsoid are equally discriminable from those represented by the point (16, 17). Two such ellipsoids are shown schematically. The question asked by Bujack et al. (1) is whether it is possible to construct a Riemannian perceptual color space such that integrating the line element along the geodesic between any two points predicts larger perceptual color differences.
See this image and copyright information in PMC

Comment on

References

    1. Bujack R., Teti E., Miller J., Caffrey E., Turton T. L., The non-Riemannian nature of perceptual color space. Proc. Natl. Acad. Sci. U.S.A. 119, e2119753119 (2022). - PMC - PubMed
    1. Shepard R. N., Toward a universal law of generalization for psychological science. Science 237, 1317–1323 (1987). - PubMed
    1. Maxwell J. C., On the theory of compound colours and the relations of the colours of the spectrum. Philos. Trans. R. Soc. Lond. 150, 57–84 (1860).
    1. Grassmann H.. Zur theorie der farbenmischung. Annalen der Physik und Chemie 165, 69–84 (1853).
    1. Brainard D. H., Stockman A., “Colorimetry” in The Optical Society of America Handbook of Optics, 3rd Edition, Volume III: Vision and Vision Optics, Bass M., et al., Eds. (McGraw Hill, New York, NY, 2010), pp. 10.11–10.56.

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