The perception of an unchanging surface color under different illuminations requires the computation of the scene-illuminant color either directly or indirectly. A possible source for the computation is the specular highlight of the surface reflection. Some issues related to color constancy are discussed, and a theory for computing the scene-illuminant chromaticity from specular highlight is described. An interesting result of the theory is that in an ideal situation, two surfaces of different colors will be sufficient for the computation.

Colour imaging technology has become almost ubiquitous in modern life in the form of monitors, liquid crystal screens, colour printers, scanners, and digital cameras. This book is a comprehensive guide to the scientific and engineering principles of colour imaging. It covers the physics of light and colour, how the eye and physical devices capture colour images, how colour is measured and calibrated, and how images are processed. It stresses physical principles and includes a wealth of real-world examples. The book will be of value to scientists and engineers in the colour imaging industry and, with homework problems, can also be used as a text for graduate courses on colour imaging.

Biostatistics and Computational Biology within the same university. His research interests include color science and imaging, multimedia security, visual sensor networks, and genomic signal processing.

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The image of a uniform wall illuminated by a spotlight often gives a strong impression of the illuminant color. How can it be possible to know if it is a white wall illuminated by yellow light or a yellow wall illuminated by white light? If the wall is a Lambertian reflector, it would not be possible to tell the difference. However, in the real world, some amount of specular reflection is often present. An empirical reflection model describes light reflection from an inhomogeneous surface as a mixture of a specular (interface) component and a diffuse (body) component. Since the spatial scale over which the interface reflection changes significantly is much smaller than that of the body reflection, it can be shown that one can effectively exploit the scale difference to find a unique solution, which is often quite accurate. The method can also be generalized to compute the illuminant chromaticity for a nonuniform smooth surface.