Depth map coding with elastic contours and 3D surface prediction

Depth maps are typically made of smooth regions separated by sharp edges. Following this rationale, this paper presents a novel coding scheme where depth data is represented by a set of contours defining the various regions together with a compact representation of the values inside each region. The proposed coding scheme is based on elastic curves, which make possible to compactly represent the contours exploiting also the temporal consistency in different frames. A 3D surface prediction algorithm is then used to obtain an accurate estimation of the depth field from the coded contours and a subsampled version of the data. Finally, an ad-hoc coding strategy for the low resolution data and the prediction residuals is presented. Experimental results prove how the proposed approach is able to obtain a very high coding efficiency outperforming the HEVC coder at medium-low bitrates.