RangeINet : fast LiDAR point cloud temporal interpolation

Due to the low scan rate of LiDAR sensors, LiDAR point cloud streams usually have a low frame rate, which is far below that of other sensors such as cameras. This could incur frame rate mismatch while conducting multi-sensor data fusion. LiDAR point cloud temporal interpolation aims to synthesize the non-existing intermediate frame between input frames to improve the frame rate of point clouds. However, the existing methods heavily depend on 3D scene flow or 2D flow estimation, which yield huge computational complexity and obstacles in real-time applications. To resolve this issue, we propose a fast and non-flow involved method, which analyzes the LiDAR point cloud by exploiting its corresponding 2D range images (RIs). Specifically, we develop a Siamese context extractor containing asymmetrical convolution kernels to learn the shape context and spatial feature of RIs, and the 3D space-time convolutions are introduced to precisely capture the temporal characteristics. Experimental results have clearly shown that our method is much faster than the state-of-the-art LiDAR point cloud temporal interpolation methods on various datasets, while delivering either comparable or superior frame interpolation performance.