LIO-SAM-GPU-ScanToMapOpt

This repository reimplements the line/plane odometry (based on LOAM) of LIO-SAM with CUDA. Replacing pcl's kdtree, a point cloud hash map (inspired by iVox of Faster-LIO) on GPU is used to accelerate 5-neighbour KNN search.

Modifications are as follow :

• The CUDA codes of the line/plane odometry are in src/cuda_plane_line_odometry.
• To use this CUDA odometry, the scan2MapOptimization() in mapOptimization.cpp is replaced with scan2MapOptimizationWithCUDA().

About

This repository reimplements the line/plane odometry in scan2MapOptimization() of mapOptimization.cpp with CUDA. The most significant cost of the original implementation is the 5-neighbour KNN search using pcl's kdtree, which, on my machine (intel i7-6700k CPU, walking_dataset.bag, with OpenMP), usually takes about 5ms. This repository replaces pcl's kdtree with a point cloud hash map (inspired by iVox of Faster-LIO) implemented with CUDA. On my machine (Nvidia 980TI CPU, walking_dataset.bag), average cost of the 5-neighbour KNN search is down to about 0.5~0.6ms, average cost of all operations in one frame is down to about 11ms. Meanwhile, other parts of the line/plane odometry (jacobians & residuals etc) are also implemented with CUDA.

Dependencies

The essential dependencies are as same as LIO-SAM, tested on Ubuntu 18.04 & Ros Melodic.

In addition, the CUDA reimplementation of the line/plane odometry requires :

• C++14
• CUDA (>= 11.0)
• CUBLAS
• thrust
• Eigen (>= 3.3.9)

How To Build

Before build this repo, some CMAKE variables in src/cuda_plane_line_odometry/CMakeLists.txt need to be modified to fit your enviroment :

set(CMAKE_CUDA_COMPILER /usr/local/cuda/bin/nvcc)       # change it to your path to nvcc
set(CUDA_TOOLKIT_ROOT_DIR /usr/local/cuda/bin/nvcc)   # change it to your path to nvcc
set(CMAKE_CUDA_ARCHITECTURES 52)                                        # for example, if your device's compute capability is 6.2, then set this CMAKE variable to 62

The basic steps to compile and run this repo is as same as LIO-SAM.

Speed-up

Acknowledgements

This repository is a modified version of LIO-SAM, whose line/plane odometry is originally based upon LOAM.

The point cloud hash map on GPU is inspired by iVox data structure of Faster-LIO, and draws experience from kdtree_cuda_builder.h of FLANN.

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