Residual path integrals for re-rendering
<|reference_start|>Residual path integrals for re-rendering: Conventional rendering techniques are primarily designed and optimized for single-frame rendering. In practical applications, such as scene editing and animation rendering, users frequently encounter scenes where only a small portion is modified between consecutive frames. In this paper, we develop a novel approach to incremental re-rendering of scenes with dynamic objects, where only a small part of a scene moves from one frame to the next. We formulate the difference (or residual) in the image between two frames as a (correlated) light-transport integral which we call the residual path integral. Efficient numerical solution of this integral then involves (1)~devising importance sampling strategies to focus on paths with non-zero residual-transport contributions and (2)~choosing appropriate mappings between the native path spaces of the two frames. We introduce a set of path importance sampling strategies that trace from the moving object(s) which are the sources of residual energy. We explore path mapping strategies that generalize those from gradient-domain path tracing to our importance sampling techniques specially for dynamic scenes. Additionally, our formulation can be applied to material editing as a simpler special case. We demonstrate speed-ups over previous correlated sampling of path differences and over rendering the new frame independently. Our formulation brings new insights into the re-rendering problem and paves the way for devising new types of sampling techniques and path mappings with different trade-offs.<|reference_end|>
@article{xu2024residual,
    title={Residual path integrals for re-rendering},
    author={Bing Xu, Tzu-Mao Li, Iliyan Georgiev, Trevor Hedstrom, Ravi
  Ramamoorthi},
    journal={arXiv preprint arXiv:2406.16302},
    year={2024},
    doi={10.1111/cgf.15152},
    archivePrefix={arXiv},
    eprint={2406.16302},
    primaryClass={cs.GR}
}