屏幕空间环境光遮挡算法研究
发布时间：2018-09-07 13:42
【摘要】：全局光照技术是真实感图形渲染的一种重要技术,传统的全局光照模型是基于物理的光传输模型,在渲染效果上可以做到非常逼真,但是其计算复杂性很高,对于一些实时图形应用并不适用。实时全局光照是近些年来发展较为迅速的一种技术,它从全局光照的组成部分出发,通过一些特殊技巧来近似达到全局光照的效果,环境光遮挡就是其中一种具有代表性的技术,它通过计算场景物体周围的几何信息来确定该物体的遮挡情况,能够渲染出非常接近真实的接触阴影效果,其计算复杂度相比传统全局光照技术要低很多。但是该技术依然不能满足实时性要求,对此人们又提出了环境光遮挡的各种改进算法。屏幕空间环境光遮挡(SSAO)算法是目前最有效的实时全局光照算法之一,在游戏等实时3D程序中应用广泛。文中详细分析了 SSAO的原理,并给出了其实现过程。针对渲染过程中的采样问题和重复计算的问题,人们通过结合延迟渲染技术和改进AO计算方式来优化SSAO。其中具有代表性的是利用帧间相关性的TSSAO算法。因采样过程而导致的噪声问题,通常采用高斯滤波和双边滤波进行平滑处理,但这两种方法都有各自的缺点,高斯滤波对于边缘部分不能很好的保留,使渲染效果不佳,双边滤波虽然在边缘问题上处理较好,但在运算效率方面任然欠佳。引导滤波技术在边缘部分的处理和计算效率上都要比前两者出色,我们通过结合引导滤波技术,对渲染纹理阶段和后处理阶段进行改进,并给出了具体的算法流程。同时对比分析了传统SSAO,TSSAO,结合引导滤波的SSAO三种算法的优劣。从结果来看,新方法可以在保持渲染效果的同时提升渲染效率。
[Abstract]:Global illumination is an important technology of realistic graphics rendering. Traditional global illumination model is based on physical optical transmission model. It can achieve very realistic rendering effect, but its computational complexity is very high. It is not suitable for some real-time graphics applications. It is a kind of technology, which starts from the components of global illumination and achieves the effect of global illumination by some special techniques. Ambient light occlusion is one of the representative technologies. It determines the occlusion of the object by calculating the geometric information around the object in the scene, and can render very close to the real contact shadow. The computational complexity of SSAO is much lower than that of traditional global illumination. However, this technology still can not meet the real-time requirements, so many improved algorithms of ambient light occlusion have been proposed. SSAO is widely used. The principle of SSAO is analyzed in detail and its implementation process is given. In view of the sampling problem and the problem of repeated computation in the rendering process, people optimize SSAO by combining the delay rendering technology with the improved AO calculation method. Gauss filtering and bilateral filtering are usually used to smooth the noise problem, but both of them have their own shortcomings. Gauss filtering can not preserve the edge very well, so the rendering effect is not good. Although bilateral filtering is good at dealing with the edge problem, it still has a poor operational efficiency. The edge processing and computational efficiency are better than the former two. We improve the texture rendering and post-processing stages by combining the bootstrap filtering technology, and give the specific algorithm flow. At the same time, the advantages and disadvantages of traditional SSAO, TSSAO and SSAO combined with bootstrap filtering are compared and analyzed. In order to maintain rendering effect while improving rendering efficiency.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41
本文编号：2228424
[Abstract]:Global illumination is an important technology of realistic graphics rendering. Traditional global illumination model is based on physical optical transmission model. It can achieve very realistic rendering effect, but its computational complexity is very high. It is not suitable for some real-time graphics applications. It is a kind of technology, which starts from the components of global illumination and achieves the effect of global illumination by some special techniques. Ambient light occlusion is one of the representative technologies. It determines the occlusion of the object by calculating the geometric information around the object in the scene, and can render very close to the real contact shadow. The computational complexity of SSAO is much lower than that of traditional global illumination. However, this technology still can not meet the real-time requirements, so many improved algorithms of ambient light occlusion have been proposed. SSAO is widely used. The principle of SSAO is analyzed in detail and its implementation process is given. In view of the sampling problem and the problem of repeated computation in the rendering process, people optimize SSAO by combining the delay rendering technology with the improved AO calculation method. Gauss filtering and bilateral filtering are usually used to smooth the noise problem, but both of them have their own shortcomings. Gauss filtering can not preserve the edge very well, so the rendering effect is not good. Although bilateral filtering is good at dealing with the edge problem, it still has a poor operational efficiency. The edge processing and computational efficiency are better than the former two. We improve the texture rendering and post-processing stages by combining the bootstrap filtering technology, and give the specific algorithm flow. At the same time, the advantages and disadvantages of traditional SSAO, TSSAO and SSAO combined with bootstrap filtering are compared and analyzed. In order to maintain rendering effect while improving rendering efficiency.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41
【参考文献】
相关期刊论文 前3条
1 李文耀;任重;;自适应的多层屏幕空间环境光遮蔽[J];计算机辅助设计与图形学学报;2011年08期
2 李艳梅;陈雷霆;刘启和;周骏;饶云波;;立即辐射度综述[J];计算机应用研究;2011年02期
3 张尤赛,陈福民;基于纹理映射与Phong光照模型的体绘制加速算法[J];中国图象图形学报;2003年09期
相关博士学位论文 前1条
1 陈皓;基于光子映射的虚拟现实真实感渲染算法研究[D];合肥工业大学;2008年
相关硕士学位论文 前2条
1 杨阳;基于点的全局光照效果的研究[D];杭州电子科技大学;2011年
2 李文耀;交互式系统中的环境光遮蔽技术研究[D];浙江大学;2011年
，本文编号：2228424
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