A geometry-bias-based photon map reconstruction and illumination estimation

作者：Cai, Peng; Kong, Dehui; Yin, Baocai^*; Zhang, Yong

来源：International Journal of Advancements in Computing Technology, 2012, 4(17): 560-570.

DOI：10.4156/ijact.vol4.issue17.65

• Curvature variation
• Geometry bias
• Global illumination
• Global photon maps
• Illumination effect
• Illumination estimation
• Photon maps
• Photorealistic images

Photon mapping can efficiently render high-quality photorealistic images with full global illumination. It stores many photons in photon map for improving estimated qualities of complex illumination, which leads to high memory overhead and long computation time. The usual methods of illumination estimation of photon map are easy to produce illumination error due to geometry bias. We give two effective solutions for these existing problems. On the one hand, this paper presents a geometry-bias-based reconstruction of photon map. Based on the number of photons and the curvature variation of surface in every non-empty grid, we take a fraction of photons in grids to reconstruct global photon map. The method has low computation cost and keeps view-independence of photon map. Compared with the non-reconstructed photon map with the same number of photons, the reconstructed photon map has far better effect of illumination estimation, and can effectively reduce all kinds of geometrically incurred illumination errors. On the other, we propose a geometry-bias-based illumination estimation of photon map. Based on true area of illumination estimation, which is intersection area between bounding sphere of photons estimating illumination and almost coplanar triangle meshes including these photons, the estimated illumination effect can be largely improved by reduction of geometry bias of illumination estimation.

• 出版日期2012-9
• 单位北京大学