Gradient-domain rendering estimates finite difference gradients of image intensities and reconstructs the final result by solving a screened Poisson problem, which shows improvements over merely sampling pixel intensities. Adaptive sampling is another orthogonal research area that focuses on distributing samples adaptively in the primal domain. However, adaptive sampling in the gradient domain with low sampling budget has been less explored. Our idea is based on the observation that signals in the gradient domain are sparse, which provides more flexibility for adaptive sampling. We propose a deep-learning-based end-to-end sampling and reconstruction framework in gradient-domain rendering, enabling adaptive sampling gradient and the primal maps simultaneously. We conducted extensive experiments for evaluation and showed that our method produces better reconstruction quality than other methods in the test dataset.

Monte Carlo (MC) integration is used ubiquitously in realistic image synthesis because of its flexibility and generality. However, the integration has to balance estimator bias and variance, which causes visually distracting noise with low sample counts. Existing solutions fall into two categories, in-process sampling schemes and post-processing reconstruction schemes. This report summarizes recent trends in the post-processing reconstruction scheme. Recent years have seen increasing attention and significant progress in denoising MC rendering with deep learning, by training neural networks to reconstruct denoised rendering results from sparse MC samples. Many of these techniques show promising results in real-world applications, and this report aims to provide an assessment of these approaches for practitioners and researchers.