Fast and accurate image generation with adaptive tables

Abstract

AbstractThe authors previously proposed the reflection integration method which generates a realistic image of objects, and the precise rendering method which accurately eliminates aliasing of images. The two methods have a common process which precisely integrates reflected lights over a unit sphere. Since this process involves a large amount of computation, accelerating the process is desired.The present paper proposes a procedure which significantly reduces the computation without sacrificing its accuracy by using an adaptive sampling table. For a part on an object where a light is sharply reflected, the reflected light sharply reduces depending on directions. The proposed procedure uses the table which nonlinearly subdivides reflection direction; precisely where a reflected light changes sharply and roughly at rest. As a result, a full‐color image can be generated with a sufficient accuracy with 90 × 90 divisions in the table. This adaptive table reduces the computation time for the integration of reflection lights on a semisphere to one‐tenth the previous method, which is equivalent to the reduction of a total image generation time by 40 to 60 percent.