Inter-Frame Compression for Dynamic Point Cloud Geometry Coding

Efficient point cloud compression is essential for applications like virtual and mixed reality, autonomous driving, and cultural heritage. In this paper, we propose a deep learning-based inter-frame encoding scheme for dynamic point cloud geometry compression. We propose a lossy geometry compression scheme that predicts the latent representation of the current frame using the previous frame by employing a novel prediction network. Our proposed network utilizes sparse convolutions with hierarchical multiscale 3D feature learning to encode the current frame using the previous frame. We employ convolution on target coordinates to map the latent representation of the previous frame to the downsampled coordinates of the current frame to predict the current frame's feature embedding. Our framework transmits the residual of the predicted features and the actual features by compressing them using a learned probabilistic factorized entropy model. At the receiver, the decoder hierarchically reconstructs the current frame by progressively rescaling the feature embedding. We compared our model to the state-of-the-art Video-based Point Cloud Compression (V-PCC) and Geometry-based Point Cloud Compression (G-PCC) schemes standardized by the Moving Picture Experts Group (MPEG). Our method achieves more than 91% BD-Rate Bjontegaard Delta Rate) reduction against G-PCC, more than 62% BD-Rate reduction against V-PCC intra-frame encoding mode, and more than 52% BD-Rate savings against V-PCC P-frame-based inter-frame encoding mode using HEVC.