Simulation of natural daylight illumination determined by a high dynamic range image

• Published in: Programming and computer software Vol. 32; no. 5; pp. 284 - 297
• Main Authors: Voloboi, A. G., Galaktionov, V. A., Kopylov, E. A., Shapiro, L. Z.
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01-10-2006
• Subjects: Algorithms; Computer graphics; Daylight; Dynamic range; Illumination; Multilayers; Simulation; Sky models; Virtual reality
• ISSN: 0361-7688; 1608-3261
• DOI: 10.1134/S0361768806050057

The use of high dynamic range images as a source of the natural daylight illumination and a background for virtual scenes containing objects with complex optic properties (fabrics, automobile multilayer paints, etc.) is considered. Physically justified algorithms for calculating the luminance of a point, recognition of the sun, generation of shadows, and background specification are considered. An analysis of the correctness of the available high dynamic range images is performed, and their drawbacks are discussed. Modifications of the algorithms are developed that correct these drawbacks in the case of simulating the illumination based on the sky models adopted by the International Commission on Illumination (CIE). The modified illumination simulation algorithms make it possible to produce more accurate images; moreover, they are automatic, and robust with respect to errors in high dynamic range images. These algorithms are used in several computer graphics systems for generating realistic images. A version of this paper with color figures can be found at http://www.keldysh.ru/pages/cgraph/publications/cgd_publ.htm.