Modeling of light transport using a modified vertex connection and merging method with multiple importance sampling

Subject of study. Realistic computer graphics based on physically correct modeling of light propagation is studied. The study addresses the problem of rendering functionally defined scenes using importance sampling to reduce variance. Multiple importance sampling (MIS) is applied to reduce computational variance; however, when the sampling strategy and weighting function do not correspond to the integrand, additional variance arises. Modeling of light transport for different types of scenes using sampling methods reveals reliability issues in rendering algorithms. Aim of study. The aim of this study is to develop a reliable MIS-based method to model light transport in various types of scenes. Method. A numerical integration approach providing improved convergence and reduced variance is proposed. Using a sampling strategy and weighting function, the sampling quality is determined for both specular and non-specular surfaces. Realistic rendering effects with a high convergence rate are obtained. Specular surfaces and their mirror shadows contain a large amount of detail with less noise. Main results. An importance sampling method is proposed to increase the reliability of light transport modeling. The approach combines a sampling method and a weighting function. Bidirectional path tracing is combined with the vertex connection and merging method while preserving the performance of the former. Practical significance. A method that effectively reduces image variance in functionally defined scenes, improves sampling quality, and generates realistic rendering effects is implemented.