Modeling of Skylight and Rendering of Outdoor Scenes

Abstract

Photorealistic animated images are extremely effective for pre-evaluating visual impact of city renewal and construction of tall buildings. In order to generate a photorealistic image not only the direct sunlight but also skylight must be considered.This paper proposes a method of high-fidelity image generation for photorealistic outdoor scenes based on the following ideas: * 1The intensity distribution of skylight taking account of scattering and absorption due to particles in the atmosphere which coincides with CIE standard skylight luminance functions is sought, and realistic images considering about spectrum distribution of skylight for any altitude of the sun can be easily and accurately displayed. * 2A rectangular parallelepiped with a specialized distribution of intensity simulating the skylight is introduced for efficient calculation of illumination due to skylight, and by employing a graphics hardware calculation of the skylight illuminance taking into account shadow effects is obtained with high efficiency- these techniques can be used to generate sequences of images, making animations possible at far lower calculation cost than previous methods.