Importance sampling with hemispherical particle footprints
Importance sampling with hemispherical particle footprints
复制标题
使用半球形粒子足迹进行重要采样
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
W. Purgathofer
中科院分区：
文献类型：
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作者：
H. Hey;W. Purgathofer
我们提出了一种新的重要性采样技术的随机光线为基础的全球照明方法。它允许通过优选地选择产生高贡献的那些采样或拍摄方向来增强具有复杂照明设置的一般场景中的全局照明计算的效率。其概率密度函数由表示预期贡献的光子贴图或重要性贴图生成。场景中给定点的出射方向是通过在该点上方的半球上制作最近邻粒子的方向足迹来选择的。通过根据粒子的方向密度自适应地选择足迹的半径，可以将射线精确地发射到多个粒子来自小立体角的高度贡献区域中。我们比较我们的新技术与现有的重要性采样技术在光子地图的全局照明模拟，并表明，我们的新技术实现了相当低的噪声水平在相同的计算时间。
We present a new importance sampling technique for stochastic ray-based global illumination methods. It allows to enhance the efficiency of global illumination calculations in general scenes with complex illumination settings by selecting preferably those sampling or shooting directions which yield a high contribution. The probability density functions for this are generated with a photon map or importance map that represents the expected contribution. An outgoing direction for a given point in the scene is selected by making directional footprints of the nearest neighbor particles onto the hemisphere above the point. By selecting the radii of the footprints adaptively according to the directional density of the particles, rays can be shot precisely into highly contributing regions where several particles come from a small solid angle. We compare our new technique with existing importance sampling techniques in photon map global illumination simulation, and show that our new technique achieves a considerably lower level of noise in the same computation time.