Accelerating Probabilistic Volumetric Mapping using Ray-Tracing Graphics Hardware

TL;DR

This paper introduces a GPU-accelerated ray-tracing method using RTX graphics hardware to significantly speed up probabilistic volumetric mapping, specifically improving the performance of Octomap in robotic navigation tasks.

Contribution

The paper presents a novel GPU-based ray-shooting approach leveraging RTX hardware to drastically enhance Octomap's efficiency in probabilistic volumetric mapping.

Findings

Over three orders of magnitude speedup in ray shooting performance

Effective mapping of octree leaf voxels to AABBs for parallel processing

Successful benchmarking with large point clouds and voxel grids

Abstract

Probabilistic volumetric mapping (PVM) represents a 3D environmental map for an autonomous robotic navigational task. A popular implementation such as Octomap is widely used in the robotics community for such a purpose. The Octomap relies on octree to represent a PVM and its main bottleneck lies in massive ray-shooting to determine the occupancy of the underlying volumetric voxel grids. In this paper, we propose GPU-based ray shooting to drastically improve the ray shooting performance in Octomap. Our main idea is based on the use of recent ray-tracing RTX GPU, mainly designed for real-time photo-realistic computer graphics and the accompanying graphics API, known as DXR. Our ray-shooting first maps leaf-level voxels in the given octree to a set of axis-aligned bounding boxes (AABBs) and employ massively parallel ray shooting on them using GPUs to find free and occupied voxels. These are fed back into CPU to update the voxel occupancy and restructure the octree. In our experiments, we have observed more than three-orders-of-magnitude performance improvement in terms of ray shooting using ray-tracing RTX GPU over a state-of-the-art Octomap CPU implementation, where the benchmarking environments consist of more than 77K points and 25K~34K voxel grids.