The realistic rendering with forward and backward photon mapping

The paper is devoted to the realistic rendering methods based on bi-directional stochastic ray tracing with photon mapping. It is proposed to use the method of progressive backward photon mapping, which allows reducing the amount of memory used to store the photon maps data, to speed up the process of calculating the indirect luminance, and to estimate the attained accuracy for each image pixel and for the entire image. Methods of combining forward and backward photon mapping for calculating different components of the image luminance and methods of efficient parallelization used to form photon maps, to trace forward and backward rays in the rendering process, and to calculate the luminance of indirect and caustic illumination components are considered. The simulation results are presented that were acquired with the developed methods and algorithms.