Progressive geometry encoder using octree-based space partitioning

A progressive 3D geometry coding scheme using octree-based space partitioning is proposed in this work, which achieves better coding efficiency than the state-of-the-art geometric codec known as the kd-tree-based codec. Given a 3D mesh, the quantized 3D vertices are first partitioned into an octree structure. The octree is then traversed from the root and gradually to the leaves and, during the traversal, each 3D cell in the tree front is subdivided along three orthogonal directions. For each cell subdivision, an 8-bit bitpattern is generated, reordered, and entropy encoded. Furthermore, selective cell subdivision is performed to provide better rate-distortion performance, especially at low bitrates. It is shown in experimental results that the coding cost is around 5.5 bits per vertex (bpv) for 8-bit coordinate quantization and 16.6 bpv for 12-bit coordinate quantization on the average. The rate-distortion performance of the proposed algorithm is significantly better than that of the kd-tree-based codec, especially at low bitrates.