We present differentiable point-based inverse rendering, DPIR, an
analysis-by-synthesis method that processes images captured under diverse
illuminations to estimate shape and spatially-varying BRDF. To this end, we
adopt point-based rendering, eliminating the need for multiple samplings per
ray, typical of volumetric rendering, thus significantly enhancing the speed of
inverse rendering. To realize this idea, we devise a hybrid point-volumetric
representation for geometry and a regularized basis-BRDF representation for
reflectance. The hybrid geometric representation enables fast rendering through
point-based splatting while retaining the geometric details and stability
inherent to SDF-based representations. The regularized basis-BRDF mitigates the
ill-posedness of inverse rendering stemming from limited light-view angular
samples. We also propose an efficient shadow detection method using point-based
shadow map rendering. Our extensive evaluations demonstrate that DPIR
outperforms prior works in terms of reconstruction accuracy, computational
efficiency, and memory footprint. Furthermore, our explicit point-based
representation and rendering enables intuitive geometry and reflectance
editing. The code will be publicly available.

提出了可微分的基于点的反渲染方法，该方法通过对在不同光照下捕获的图像进行分析合成，估计形状和空间变化的 BRDF。利用混合的基于点和基于体素的几何表示进行快速渲染，并通过正则化基函数的 BRDF 表示来缓解反渲染的无意义性。通过点阴影图渲染提出了一种高效的阴影检测方法。在计算准确性、计算效率和内存占用等方面，DPIR 优于之前的工作。同时，显式的基于点的表示和渲染使得几何和反射的编辑变得直观。