Rendering of spherical light fields

Abstract

A plenoptic function is a parameterized function describing the flow of light in space, and has served as a key idea in building some of the recent image based rendering systems. The paper presents a new representation scheme, called a spherical light field, of the plenoptic function, that is based on spheres. While methods using spherical coordinates are thought to require substantially more computation than those using planar or cylindrical coordinates, we show that spheres can also be used efficiently in representing and resampling the flow of light. Our image based rendering algorithm is different from the previous systems, the light field and lumigraph, in that it is an "object space" algorithm that can be easily embedded into the traditional polygonal rendering system. Our method is easily accelerated by 3D graphics boards that support the primitive functionality, such as viewing and smooth shading. In addition, we introduce an encoding scheme based on wavelets for compression of the huge data resulting from sampling of the spherical light field. The proposed technique can be easily adapted to compress the light field and lumigraph data, and offers as high compression ratios as the previous methods. Furthermore, it naturally creates a multi resolutional representation of the light flow that can be exploited effectively in the future applications. We show how to access the compressed data efficiently using a modified significance map and an incremental decoding technique, and report experimental results on several test data sets.