Time-of-flight (ToF) devices have greatly propelled the advancement of various multi-modal perception applications. However, achieving accurate rendering of time-resolved information remains a challenge, particularly in scenes involving complex geometries, diverse materials and participating media. Existing ToF rendering works have demonstrated notable results, yet they struggle with scenes involving scattering media and camera-warped settings. Other steady-state volumetric rendering methods exhibit significant bias or variance when directly applied to ToF rendering tasks. To address these challenges, we integrate transient diffusion theory into path construction and propose novel sampling methods for free-path distance and scattering direction, via resampled importance sampling and offline tabulation. An elliptical sampling method is further adapted to provide controllable vertex connection satisfying any required photon traversal time. In contrast to the existing temporal uniform sampling strategy, our method is the first to consider the contribution of transient radiance to importance-sample the full path, and thus enables improved temporal path construction under multiple scattering settings. The proposed method can be integrated into both path tracing and photon-based frameworks, delivering significant improvements in quality and efficiency with at least a 5x MSE reduction versus SOTA methods in equal rendering time.

中文翻译：

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DARTS：在均匀散射介质中进行飞行时间渲染的扩散近似残差时间采样


飞行时间 （ToF） 设备极大地推动了各种多模态感知应用的发展。然而，实现时间分辨信息的准确渲染仍然是一项挑战，尤其是在涉及复杂几何图形、各种材料和参与媒体的场景中。现有的 ToF 渲染工作已经展示了显着的结果，但它们在涉及散射媒体和摄像机扭曲设置的场景中遇到了困难。其他稳态体积渲染方法在直接应用于 ToF 渲染任务时表现出明显的偏差或方差。为了应对这些挑战，我们将瞬态扩散理论整合到路径构建中，并通过重采样重要性采样和离线制表，为自由路径距离和散射方向提出了新的采样方法。进一步适于提供满足任何所需光子遍历时间的可控顶点连接。与现有的时间均匀采样策略相比，我们的方法是第一个考虑瞬态辐射对完整路径进行重要采样的贡献的方法，从而可以在多个散射设置下改进时间路径构造。所提出的方法可以集成到路径追踪和基于光子的框架中，在相同的渲染时间内，与 SOTA 方法相比，MSE 至少减少了 5 倍，从而显著提高了质量和效率。