VoxelCache: Accelerating Online Mapping in Robotics and 3D Reconstruction Tasks

TL;DR

VoxelCache is a hardware-software solution that leverages spatial locality in 3D mapping to significantly accelerate voxel data access, enabling faster real-time mapping in resource-constrained robotic and visualization systems.

Contribution

The paper introduces VoxelCache, a novel caching technique that exploits access patterns in 3D mapping to improve data access speeds on CPUs and GPUs.

Findings

Average speedup of 1.47X on CPUs

Up to 1.66X speedup on CPUs

Average speedup of 1.79X on GPUs

Abstract

Real-time 3D mapping is a critical component in many important applications today including robotics, AR/VR, and 3D visualization. 3D mapping involves continuously fusing depth maps obtained from depth sensors in phones, robots, and autonomous vehicles into a single 3D representative model of the scene. Many important applications, e.g., global path planning and trajectory generation in micro aerial vehicles, require the construction of large maps at high resolutions. In this work, we identify mapping, i.e., construction and updates of 3D maps to be a critical bottleneck in these applications. The memory required and access times of these maps limit the size of the environment and the resolution with which the environment can be feasibly mapped, especially in resource constrained environments such as autonomous robot platforms and portable devices. To address this challenge, we propose VoxelCache: a hardware-software technique to accelerate map data access times in 3D mapping applications. We observe that mapping applications typically access voxels in the map that are spatially co-located to each other. We leverage this temporal locality in voxel accesses to cache indices to blocks of voxels to enable quick lookup and avoid expensive access times. We evaluate VoxelCache on popularly used mapping and reconstruction applications on both GPUs and CPUs. We demonstrate an average speedup of 1.47X (up to 1.66X) and 1.79X (up to 1.91X) on CPUs and GPUs respectively.