Chroma Subsampling for Enhanced Geometry-Based Point Cloud Compression

Due to the huge data volume of three dimensional point clouds, efficient point cloud compression (PCC) is very important and challenging under limited storage and bandwidth conditions. The Moving Picture Experts Group (MPEG) is actively developing the geometry-based point cloud compression (G-PCC) standard and plan to release the second edition of G-PCC, namely Enhanced G-PCC. In image and video compression, chroma components are typically encoded at a lower resolution than luma, with minimal perceptual quality loss. However, chroma subsampling has not yet been explored in PCC. We investigate the characteristics of points at different level of details, and propose a chroma subsampling that can be embedded with the codec of Enhanced G-PCC. Experimental results show that the proposed method outperforms the state-of-the-art Enhanced G-PCC reference software version29.0 in terms of coding efficiency and time complexity. Due to the excellent performance, the proposed method has been adopted by the MPEG and will be integrated into the upcoming version of the reference software of Enhanced G-PCC.