改进的基于屏幕空间环境遮挡  

Improved Screen Space Ambient Occlusion

作　　者：邱祥松 李泽昇[2] 吴志红[1,2] 时宏伟[2] 张严辞[1,2] 

机构地区：[1]四川大学计算机学院,成都610065 [2]四川大学视觉合成图形图像技术国防重点学科实验室,成都610065

出　　处：《计算机学报》2014年第3期642-648,共7页Chinese Journal of Computers

基　　金：国家自然科学基金(60903118);国家科技支撑计划(2012BAH62F03)资助~~

摘　　要：基于屏幕空间环境遮挡以牺牲计算精度与部分效果作为代价,换取场景的实时渲染.文中针对基于屏幕空间环境遮挡技术在采样方式、遮挡因子计算和平滑滤波3个方面的缺陷,提出相应的改进方法.采样方式方面,在三维空间构建平行于投影平面的圆盘,并根据其在屏幕的投影来计算采样范围,然后采用类似正态分布的方法结合随机纹理,对采样范围内的纹素采样;在遮挡因子计算方面,增加衰减系数,调整采样点对遮挡因子的贡献;最后,使用双边滤波来平滑图像,保持场景边缘,突出细节信息.Screen-space ambient occlusion algorithm achieves real-time rendering speed at the cost of precision and visual effects. This paper presents an improved screen-based ambient occlu- sion algorithm which addresses the following three issues, sampling process, computation of occlusion factor and smooth filter. With respect to the sampling process, a more accurate sam- pling region of the pixels in image space is determined by projecting a 3D circle disk in the image plane. Then the sampling process is improved by combining the normal distribution with random texture. Some coefficients are added in the occlusion computation formula to adjust the contribu- tion of sampled points. Finally, bilateral filter is employed to smooth the image, which keeps the edges and highlight more details.

关 键 词：环境遮挡 屏幕空间 圆盘采样 双边滤波 光线跟踪中图法 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]