用可学习的高斯光子场替代传统光子映射,实现多视角高效渲染。
From Particles to Fields: Reframing Photon Mapping with Continuous Gaussian Photon Fields
- 将光子分布建模为可学习的3D高斯体,形成连续可复用的辐射度函数。
- 在包含焦散等复杂光照的场景中,精度接近传统方法但计算量降低数量级。
- 适合需要高保真光照且需多视角快速渲染的工业级图像合成任务。
精确建模光传输对真实感图像合成至关重要。光子映射能提供复杂全局光照(如焦散、镜面-漫反射交互)的物理可信估计,但在渲染同一场景的多个视角时,其每视点的辐射度估计效率低下。这是由于每个视角独立进行光子追踪和随机核估计,导致大量重复计算。为加速多视角渲染,本文将光子映射重构为连续可重用的辐射度函数。具体地,提出高斯光子场(Gaussian Photon Field, GPF),一种可学习的表示,将光子分布编码为由位置、旋转、尺度和光谱参数化的各向异性3D高斯基元。GPF初始由首次SPPM迭代中的物理光子生成,并通过多视角最终辐射度监督进行优化,将基于光子的光传输知识提炼为连续场。训练完成后,该场支持沿相机射线的可微辐射度评估,无需重复光子追踪或迭代优化。在包含焦散与镜面-漫反射交互的复杂光照场景上的大量实验表明,GPF实现了光子级精度,同时计算开销降低数个数量级,统一了基于光子渲染的物理严谨性与神经场景表示的高效性。
原文摘要 · Abstract (English)
Accurately modeling light transport is essential for realistic image synthesis. Photon mapping provides physically grounded estimates of complex global illumination effects such as caustics and specular-diffuse interactions, yet its per-view radiance estimation remains computationally inefficient when rendering multiple views of the same scene. The inefficiency arises from independent photon tracing and stochastic kernel estimation at each viewpoint, leading to inevitable redundant computation. To accelerate multi-view rendering, we reformulate photon mapping as a continuous and reusable radiance function. Specifically, we introduce the Gaussian Photon Field (GPF), a learnable representation that encodes photon distributions as anisotropic 3D Gaussian primitives parameterized by position, rotation, scale, and spectrum. GPF is initialized from physically traced photons in the first SPPM iteration and optimized using multi-view supervision of final radiance, distilling photon-based light transport into a continuous field. Once trained, the field enables differentiable radiance evaluation along camera rays without repeated photon tracing or iterative refinement. Extensive experiments on scenes with complex light transport, such as caustics and specular-diffuse interactions, demonstrate that GPF attains photon-level accuracy while reducing computation by orders of magnitude, unifying the physical rigor of photon-based rendering with the efficiency of neural scene representations.
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