k-DOP Clipping: Robust Ghosting Mitigation in Temporal Antialiasing

Temporal antialiasing is one of the most common methods for removing aliasing artifacts in contemporary real-time rendering, based on utilizing reprojected color data from previous frames. One typical issue with the method is ghosting: moving objects leaving a wake of visual trails. To mitigate this, a common technique is to validate and rectify reused history colors by comparing and clipping them to the color neighborhoods of the current frame’s pixels. Previous, bounding box based methods are only situationally effective and cause significant ghosting in less favorable circumstances. We propose using k-Discrete Oriented Polytopes (“k-DOPs”) for more robust neighborhood clipping. For a 0.2 ms performance overhead, our method more reliably mitigates ghosting across scenes where previous methods have inconsistent results.