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Proceedings Paper

Can color-space transformation improve color computations other than von Kries?
Author(s): Michael H. Brill
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Paper Abstract

Three-dimensional objects in an image, which appear with shading and cast shadows, can be difficult to recognize as single entities, and there can also be problems recognizing the colors of the objects independent of the spectrum of illumination. The removal of shading and cast shadows has often been done in remote sensing by the band-ratio algorithm. A ratio of red to green bands cancels variations of incident light intensity between different points on the same matte object. Finlayson et al. showed that, for physically reasonable illuminant and reflectance spectra, von Kries adaptation gives exact color constancy if a particular linear transformation on the color-matching functions is performed prior to adaptation. The present paper extends this approach to band ratios, and also to the related color-constancy model of Judd (which subtracts the white-reflectance chromaticity instead of dividing by the white-reflectance tristimulus values as von Kries adaptation does). In both cases, invariance requires the illuminant basis functions to be metameric (up to a scale factor) -- with respect to the reference white in the case of Judd adaptation, and with respect to all reflectances in the case of band ratios. The von Kries theory thus seems unique among the simple processing methods.

Paper Details

Date Published: 8 September 1993
PDF: 8 pages
Proc. SPIE 1913, Human Vision, Visual Processing, and Digital Display IV, (8 September 1993); doi: 10.1117/12.152723
Show Author Affiliations
Michael H. Brill, Science Applications International Corp. (United States)


Published in SPIE Proceedings Vol. 1913:
Human Vision, Visual Processing, and Digital Display IV
Jan P. Allebach; Bernice E. Rogowitz, Editor(s)

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