Reducing Wedgelet lookup table size with down-sampling for depth map coding in 3D-HEVC

In 3D-HEVC, a new coding standard of 3D video, Explicit Wedgelet mode within Depth Modelling Modes (DMM) partitions a depth block into two non-rectangular regions using a Wedgelet pattern selected from a Wedgelet lookup table. The Wedgelet lookup table is constructed during both encoder and decoder initialization for each block size ranging from 4×4 to 16×16, while the Wedgelet lookup table consists of a large number of Wedgelet bi-patterns, which involves relatively high computational complexity and may cause cache storing problem. In this paper, we propose a down-sampling method to reduce the number of Wedgelet patterns in the Wedgelet lookup table. The experimental results show our proposed down-sampling method can achieve storage size reduction by 27.8% with negligible 0.03% and 0.05% coding loss in both configurations of Common Test Conditions (CTC) and All Intra (AI), respectively.