UniPCGC: Towards Practical Point Cloud Geometry Compression via an Efficient Unified Approach

We propose an efficient unified point cloud geometry compression framework UniPCGC. It is a lightweight framework that supports lossy compression, lossless compression, variable rate and variable complexity.

First, we introduce the Uneven 8-Stage Lossless Coder (UELC) in the lossless mode, which allocates more computational complexity to groups with higher coding difficulty, and merges groups with lower coding difficulty. Second, Variable Rate and Complexity Module (VRCM) is achieved in the lossy mode through joint adoption of a rate modulation module and dynamic sparse convolution. Finally, through the dynamic combination of UELC and VRCM, we achieve lossy compression, lossless compression, variable rate and complexity within a unified framework.

Compared to the previous state-of-the-art method, our method achieves a compression ratio (CR) gain of 8.1% on lossless compression, and a Bjontegaard Delta Rate (BD-Rate) gain of 14.02% on lossy compression, while also supporting variable rate and variable complexity.

In this section, we detail the components of the UniPCGC framework, explaining how each part contributes to the overall efficiency and effectiveness of the compression process.

In each stage, the previously coding groups and their features are regarded as prior information to better estimate the occupancy probability of groups in the current stage.

Detailed architecture of proposed VRCM. It also shows the architecture of channel level bit allocation module, One-Stage Lossless Coder (OLC / DOLC) and Dynamic Feature Extraction Layer (DFEL).

In this section, we demonstrate the performance of our approach for both lossless and lossy compression.