Spectral sharpening - Sensor transformations for improved color constancy

Finlayson, Graham D., Drew, Mark S. and Funt, Brian V. (1994) Spectral sharpening - Sensor transformations for improved color constancy. Journal of the Optical Society of America A: Optics and image science, 11 (5). pp. 1553-1563. ISSN 0740-3232

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Abstract

We develop sensor transformations, collectively called spectral sharpening, that convert a given set of sensor sensitivity functions into a new set that will improve the performance of any color-constancy algorithm that is based on an independent adjustment of the sensor response channels. Independent adjustment of multiplicative coefficients corresponds to the application of a diagonal-matrix transform (DMT) to the sensor response vector and is a common feature of many theories of color constancy, Land’s retinex and von Kries adaptation in particular. We set forth three techniques for spectral sharpening. Sensor-based sharpening focuses on the production of new sensors as linear combinations of the given ones such that each new sensor has its spectral sensitivity concentrated as much as possible within a narrow band of wavelengths. Data-based sharpening, on the other hand, extracts new sensors by optimizing the ability of a DMT to account for a given illumination change by examining the sensor response vectors obtained from a set of surfaces under two different illuminants. Finally in perfect sharpening we demonstrate that, if illumination and surface reflectance are described by two- and three-parameter finite-dimensional models, there exists a unique optimal sharpening transform. All three sharpening methods yield similar results. When sharpened cone sensitivities are used as sensors, a DMT models illumination change extremely well. We present simulation results suggesting that in general nondiagonal transforms can do only marginally better. Our sharpening results correlate well with the psychophysical evidence of spectral sharpening in the human visual system.

Item Type:	Article
Uncontrolled Keywords:	spectral sharpening,color constancy,color balancing,lightness,vonkries adaptation
Faculty \ School:	Faculty of Science > School of Computing Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Colour and Imaging Lab Faculty of Science > Research Groups > Visual Computing and Signal Processing
Depositing User:	Pure Connector
Date Deposited:	17 Nov 2014 12:40
Last Modified:	15 Jul 2025 09:35
URI:	https://ueaeprints.uea.ac.uk/id/eprint/50971
DOI:	10.1364/josaa.11.001553

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