Tighter error bounds and weighted error metrics for hierarchical radiosity

Abstract

In this paper we first derive a tighter error bound on form factors as a subdivision criterion for the hierarchical radiosity algorithm. Such an error bound can reduce more unnecessary links and improve the performance of the hierarchical radiosity algorithm to meet a user-specified error tolerance. We then propose a weighted error metric in form factor computation such that more effort is automatically applied to shadow boundaries. Evaluating form factors along shadow boundaries with a higher degree of precision should enhance the quality of human perception. Using the proposed tighter error bound on the weighted error metric, we not only improve the performance but also increase the accuracy of the hierarchical radiosity algorithm.