标题：Adaptive Photon Mapping Based on Gradient
作者：Kang, Chun-Meng; Wang, Lu; Xu, Yan-Ning; Meng, Xiang-Xu; Song, Yuan-Jie
作者机构：[Kang, C.-M] School of Computer Science and Technology, Shandong University, Jinan, 252000, China, Engineering Research Center of Digital Media Techno 更多
通讯作者地址：[Wang, L]Shandong Univ, Sch Comp Sci & Technol, Jinan 252000, Peoples R China.
关键词：photo-realistic rendering;global illumination;photon mapping;radiance estimation
摘要：Photon mapping can simulate some special effects e?ciently such as shadows and caustics. Photon mapping runs in two phases: the photon map generating phase and the radiance estimation phase. In this paper, we focus on the bandwidth selection process in the second phase, as it can affect the final quality significantly. Poor results with noise arise if few photons are collected, while bias appears if a large number of photons are collected. In order to solve this issue, we propose an adaptive radiance estimation solution to obtain trade-offs between noise and bias by changing the number of neighboring photons and the shape of the collected area according to the radiance gradient. Our approach can be applied in both the direct and the indirect illumination computation. Finally, experimental results show that our approach can produce smoother quality while keeping the high frequency features perfectly compared with the original photon mapping algorithm.