RTX-RSim: Accelerated Vulkan Room Response Simulation for Time-of-Flight Imaging

Time-of-Flight camera systems are an essential component in 3D scene analysis and reconstruction for many modern computer vision applications. The development and validation of such systems requires testing in a large variety of scenes and situations. Accurate room impulse response simulation greatly speeds up development and validation, as well as reducing its cost, but large computational overhead has so far limited its applicability. While the overall algorithmic requirements of this simulation differ significantly from 3D rendering, the recently introduced hardware raytracing support in GPUs nonetheless provides an interesting new implementation option. In this paper, we present a new room impulse simulation method, implemented with Vulkan compute shaders and leveraging NVIDIA VKRay hardware raytracing. We also extend this method to asynchronous streaming in order to overcome the limitations of on-board GPU memory when simulating very large scenes. Our implementation is, to the best of our knowledge, the first ever application of Vulkan hardware raytracing in a non-rendering simulation setting. Compared to a state-of-the-art multicore CPU implementation running on 12 CPU cores, we achieve an overall speedup of factor 20.9 when streaming is not required, and 17.6 with streaming, on a single consumer GPU.