Rate-Distortion Optimized Variable-Node-size Trisoup for Point Cloud Coding

Triangle soup (Trisoup) is being studied as a new coding tool for Geometry-based Point Cloud Compression (G-PCC) stan-dardized in the Moving Picture Experts Group (MPEG). Outside of MPEG, a variable-node-size extension of Trisoup is studied to increase the flexibility of G-PCC. A primary advantage of variable node size is to achieve better coding performance by selecting appropriate node size according to local geometric complexity and required bits. However, the node size is not optimized in terms of bit rate and distortion in the conventional extension. To maximize the coding performances of the variable-node-size method, we propose a new cost function considering both bit rates and distortions. The experimental results show that the proposed method provides -1.5 % coding performance improvement in point-to-point PSNR versus bit rate against the conventional extension.