Implicit Geometry Partition for Point Cloud Compression

Octree (OT) geometry partitioning has been acknowledged as an efficient representation in state-of-the-art point cloud compression (PCC). In this work, a new geometry partition and coding scheme is proposed to improve the OT based coding framework, in which the quad-tree (QT) and binary-tree (BT) partitions are introduced. It brings in and harmonizes the asymmetric kd-tree like concept with the symmetric OT-based geometry coding framework. It also enables asymmetric bounding boxes that can better fit the shape of 3D scenes. Bit savings can be obtained by skipping encoding unnecessary bits from implicit QT and BT partitions. Parameters are introduced to specify the conditions on which implicit geometry partitions will be applied. Experimental results have shown significant coding gains over the OT-only coding scheme in the state-of-the-art test model of MPEG Geometry based PCC (G-PCC) standard. For the dynamically acquired point clouds, the average coding gains are 8.3% for lossy geometry coding and 4.8% for lossless geometry coding without significant increase in coding complexity.