  For the SLAM system in robotics and autonomous driving, the accuracy of
front-end odometry and back-end loop-closure detection determine the whole
intelligent system performance. But the LiDAR-SLAM could be disturbed by
current scene moving objects, resulting in drift errors and even loop-closure
failure. Thus, the ability to detect and segment moving objects is essential
for high-precision positioning and building a consistent map. In this paper, we
address the problem of moving object segmentation from 3D LiDAR scans to
improve the odometry and loop-closure accuracy of SLAM. We propose a novel 3D
Sequential Moving-Object-Segmentation (3D-SeqMOS) method that can accurately
segment the scene into moving and static objects, such as moving and static
cars. Different from the existing projected-image method, we process the raw 3D
point cloud and build a 3D convolution neural network for MOS task. In
addition, to make full use of the spatio-temporal information of point cloud,
we propose a point cloud residual mechanism using the spatial features of
current scan and the temporal features of previous residual scans. Besides, we
build a complete SLAM framework to verify the effectiveness and accuracy of
3D-SeqMOS. Experiments on SemanticKITTI dataset show that our proposed
3D-SeqMOS method can effectively detect moving objects and improve the accuracy
of LiDAR odometry and loop-closure detection. The test results show our
3D-SeqMOS outperforms the state-of-the-art method by 12.4%. We extend the
proposed method to the SemanticKITTI: Moving Object Segmentation competition
and achieve the 2nd in the leaderboard, showing its effectiveness.
