Multi-layer screen-space ambient occlusion using hybrid sampling

ISCAS OpenIR

	Multi-layer screen-space ambient occlusion using hybrid sampling
	Liu, Fang (1); Song, Yunpeng (3); Liu, Xuehui (2); Xu, Xianchao (3)
	2013
会议名称	12th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and Its Applications in Industry, VRCAI 2013
页码	71-75
会议日期	November 17, 2013 - November 19, 2013
会议地点	Hong Kong, Hong kong
收录类别	EI
出版地	Association for Computing Machinery, General Post Office, P.O. Box 30777, NY 10087-0777, United States
ISBN	9781450325905
部门归属	(1) State Key Lab. of Computer Sciences, Institute of Software, Chinese Academy of Sciences, China; (2) SuperComputing Center, Computer Network Information Center, Chinese Academy of Sciences, China; (3) Intel Labs. of China, China
摘要	Ambient occlusion is a shading method which approximates the global illumination by taking into account attenuation of light due to occlusion[Christensen 2002; Sergey et al. 1998; Andrei et al. 2003]. Screen-space ambient occlusion is a scene-independent improvement which performs the visibility test using depth buffer on GPU in real time. Shanmugam et al. [Shanmugam et al. 2007] proposes a real-time multi-pass hardware assisted ambient occlusion method. The algorithm randomly samples the normal/depth buffer and reconstructs the surface using spheres that can be projected to screen, but has the overocclusion issue. Bavoil et al. [Bavoil et al. 2008] approximates the ambient occlusion illumination using a image-space horizon-based method. However, the scenes will also be overoccluded due to the inconsideration of the layers behind the frontmost one. Moreover, the rough approximation of the geometry occluder makes the shadows lack of rich details. In this paper we propose a new solution to approximate ambient occlusion using a hybrid sampling method of both above methods. The surfaces can be more accurately depicted using spheres and the geometry occluder under the horizon plane can be discarded to address the overocclusion issue. In addition, a multi-layer method is utilized to future alleviate overocclusion using the depth information of all the layers. Experiments show that our algorithm can generate more realistic results for complex scenes with rich details, with comparable performance. © 2013 ACM.; Ambient occlusion is a shading method which approximates the global illumination by taking into account attenuation of light due to occlusion[Christensen 2002; Sergey et al. 1998; Andrei et al. 2003]. Screen-space ambient occlusion is a scene-independent improvement which performs the visibility test using depth buffer on GPU in real time. Shanmugam et al. [Shanmugam et al. 2007] proposes a real-time multi-pass hardware assisted ambient occlusion method. The algorithm randomly samples the normal/depth buffer and reconstructs the surface using spheres that can be projected to screen, but has the overocclusion issue. Bavoil et al. [Bavoil et al. 2008] approximates the ambient occlusion illumination using a image-space horizon-based method. However, the scenes will also be overoccluded due to the inconsideration of the layers behind the frontmost one. Moreover, the rough approximation of the geometry occluder makes the shadows lack of rich details. In this paper we propose a new solution to approximate ambient occlusion using a hybrid sampling method of both above methods. The surfaces can be more accurately depicted using spheres and the geometry occluder under the horizon plane can be discarded to address the overocclusion issue. In addition, a multi-layer method is utilized to future alleviate overocclusion using the depth information of all the layers. Experiments show that our algorithm can generate more realistic results for complex scenes with rich details, with comparable performance. © 2013 ACM.
语种	英语
内容类型	会议论文
URI标识	http://ir.iscas.ac.cn/handle/311060/16688
专题	中国科学院软件研究所
推荐引用方式 GB/T 7714	Liu, Fang ,Song, Yunpeng ,Liu, Xuehui ,et al. Multi-layer screen-space ambient occlusion using hybrid sampling[C]. Association for Computing Machinery, General Post Office, P.O. Box 30777, NY 10087-0777, United States,2013:71-75.