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Shape, Light, Material Decomposition from Images Using Monte Carlo Rendering (arxiv.org)
3 points by lnyan on Jun 8, 2022 | hide | past | pdf | discuss on HN

In plain words: Instead of simple direct lighting, it shades images with ray tracing and averages many random light paths, then cleans up the noise so optimization can learn shape, materials, and lighting. This separates materials from lights better than the usual simple shading, with few samples.

Abstract · Shape, Light, and Material Decomposition from Images using Monte Carlo Rendering and Denoising

Recent advances in differentiable rendering have enabled high-quality reconstruction of 3D scenes from multi-view images. Most methods rely on simple rendering algorithms: pre-filtered direct lighting or learned representations of irradiance. We show that a more realistic shading model, incorporating ray tracing and Monte Carlo integration, substantially improves decomposition into shape, materials & lighting. Unfortunately, Monte Carlo integration provides estimates with significant noise, even at large sample counts, which makes gradient-based inverse rendering very challenging. To address this, we incorporate multiple importance sampling and denoising in a novel inverse rendering pipeline. This substantially improves convergence and enables gradient-based optimization at low sample counts. We present an efficient method to jointly reconstruct geometry (explicit triangle meshes), materials, and lighting, which substantially improves material and light separation compared to previous work. We argue that denoising can become an integral part of high quality inverse rendering pipelines.

Jon Hasselgren, Nikolai Hofmann, Jacob Munkberg
arXiv:2206.03380 · cs.GR, cs.CV · submitted Jun 7, 2022 · updated Oct 4, 2022
abstract · pdf · html · Project website: https://nvlabs.github.io/nvdiffrecmc/

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