NVIDIA Corporation
ADAPTIVE TEMPORAL IMAGE FILTERING FOR RENDERING REALISTIC ILLUMINATION

Abstract:

Robust temporal gradients, representing differences in shading results, can be computed between current and previous frames in a temporal denoiser for ray-traced renderers. Backward projection can be used to locate matching surfaces, with the relevant parameters of those surfaces being carried forward and used for patching. Backward projection can be performed for each stratum in a current frame, a stratum representing a set of adjacent pixels. A pixel from each stratum is selected that has a matching surface in the previous frame, using motion vectors generated during the rendering process. A comparison of the depth of the normals, or the visibility buffer data, can be used to determine whether a given surface is the same in the current frame and the previous frame, and if so then parameters of the surface from the previous frame G-buffer is used to patch the G-buffer for the current frame.