Abstract

This work is devoted to the study of photon mapping methods applied to realistic rendering. In distinction from the conventional rendering methods, the calculation of the indirect and caustic luminance is based on backward photon maps (which are also called observation maps). The main advantages of this method are described. These advantages are the natural distribution of the photons in the regions forming the image luminance and the reduction of the number of photons formed on the trace of one ray. The main algorithmic difficulty of the backward photon mapping method is discussed, which is the necessity to synchronize data access during the calculations and accumulate the luminance due to indirect and caustic illuminance. To resolve this difficulty, it is proposed to use intermediate photon maps of the indirect and caustic illumination distributed over the computation threads that render the corresponding parts of the image. Based on this analysis, the method of progressive backward photon mapping is introduced, and an algorithm of realistic rendering based on this method is described. The proposed algorithm does not require additional synchronization during the accumulation of luminance at the image points, which makes it possible to efficiently implement it not only on the central processor but also on graphics processors (GPUs). Results of the qualitative and quantitative comparison of the rendering results produced by the methods of progressive forward and backward photon mapping are presented.

中文翻译：

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渐进后向光子映射

摘要

这项工作致力于研究应用于逼真渲染的光子映射方法。与传统的渲染方法不同，间接和焦散亮度的计算是基于后向光子图（也称为观察图）。描述了这种方法的主要优点。这些优点是光子在形成图像亮度的区域中的自然分布以及在一条光线的轨迹上形成的光子数量的减少。讨论了反向光子映射方法的主要算法难点，即在计算过程中同步数据访问的必要性，以及由于间接和焦散光照而累积的亮度。为了解决这个困难，建议使用分布在渲染图像相应部分的计算线程上的间接和焦散照明的中间光子图。在此分析的基础上，介绍了渐进后向光子映射方法，并描述了基于该方法的逼真渲染算法。所提出的算法在图像点的亮度累积过程中不需要额外的同步，这使得它不仅可以在中央处理器上而且在图形处理器（GPU）上高效地实现。介绍了由渐进前向和后向光子映射方法产生的渲染结果的定性和定量比较结果。在此分析的基础上，介绍了渐进后向光子映射方法，并描述了基于该方法的逼真渲染算法。所提出的算法在图像点的亮度累积过程中不需要额外的同步，这使得它不仅可以在中央处理器上而且在图形处理器（GPU）上高效地实现。介绍了由渐进前向和后向光子映射方法产生的渲染结果的定性和定量比较结果。在此分析的基础上，介绍了渐进后向光子映射方法，并描述了基于该方法的逼真渲染算法。所提出的算法在图像点的亮度累积过程中不需要额外的同步，这使得它不仅可以在中央处理器上而且在图形处理器（GPU）上高效地实现。介绍了由渐进前向和后向光子映射方法产生的渲染结果的定性和定量比较结果。这使得它不仅可以在中央处理器上而且还可以在图形处理器 (GPU) 上高效实现。介绍了由渐进前向和后向光子映射方法产生的渲染结果的定性和定量比较结果。这使得它不仅可以在中央处理器上而且还可以在图形处理器 (GPU) 上高效实现。介绍了由渐进前向和后向光子映射方法产生的渲染结果的定性和定量比较结果。