Inverse rendering with Gaussian Splatting has advanced rapidly, but accurately disentangling material properties from complex global illumination effects, particularly indirect illumination, remains a major challenge. Existing methods often query indirect radiance from Gaussian primitives pre-trained for novel-view synthesis. However, these pre-trained Gaussian primitives are supervised only towards limited training viewpoints, thus lack supervision for modeling indirect radiances from unobserved views. To address this issue, we introduce radiometric consistency, a novel physically-based constraint that provides supervision towards unobserved views by minimizing the residual between each Gaussian primitive's learned radiance and its physically-based rendered counterpart. Minimizing the residual for unobserved views establishes a self-correcting feedback loop that provides supervision from both physically-based rendering and novel-view synthesis, enabling accurate modeling of inter-reflection. We then propose Radiometrically Consistent Gaussian Surfels (RadioGS), an inverse rendering framework built upon our principle by efficiently integrating radiometric consistency by utilizing Gaussian surfels and 2D Gaussian ray tracing. We further propose a finetuning-based relighting strategy that adapts Gaussian surfel radiances to new illuminations within minutes, achieving low rendering cost (<10ms). Extensive experiments on existing inverse rendering benchmarks show that RadioGS outperforms existing Gaussian-based methods in inverse rendering, while retaining the computational efficiency.

翻译：基于高斯泼溅的逆向渲染技术发展迅速，但准确从复杂全局光照效应（特别是间接光照）中解耦材质属性仍是一项重大挑战。现有方法通常从为新颖视角合成而预训练的高斯基元中查询间接辐射度。然而，这些预训练高斯基元仅针对有限训练视角进行监督，因此在建模未观测视角的间接辐射度时缺乏监督。为解决此问题，我们引入辐射一致性这一新颖的物理约束，通过最小化每个高斯基元学习到的辐射度与其基于物理的渲染对应值之间的残差，为未观测视角提供监督。针对未观测视角最小化残差可建立一个自校正反馈循环，该循环同时提供基于物理渲染和新颖视角合成的监督，从而实现对相互反射的精确建模。基于此原理，我们提出辐射一致性高斯面元，这是一个通过利用高斯面元和二维高斯光线追踪高效集成辐射一致性的逆向渲染框架。我们进一步提出基于微调的重新光照策略，可在数分钟内使高斯面元辐射度适应新光照条件，同时实现低渲染成本。在现有逆向渲染基准上的大量实验表明，RadioGS在逆向渲染任务中优于现有基于高斯的方法，同时保持了计算效率。