Scalable Mesh Representation for Depth from Breakpoint-Adaptive Wavelet Coding

A highly scalable and compact representation of depth data is required in many applications, and it is especially critical for plenoptic multiview image compression frameworks that use depth information for novel view synthesis and inter-view prediction. Efficiently coding depth data can be difficult as it contains sharp discontinuities. Breakpoint-adaptive discrete wavelet transforms (BPA-DWT) currently being standardized as part of JPEG 2000 Part-17 extensions have been found suitable for coding spatial media with hard discontinuities. In this paper, we explore a modification to the original BPA-DWT by replacing the traditional constant extrapolation strategy with the newly proposed affine extrapolation for reconstructing depth data in the vicinity of discontinuities. We also present a depth reconstruction scheme that can directly decode the BPA-DWT coefficients and breakpoints onto a compact and scalable mesh-based representation which has many potential benefits over the sample-based description. For performing depth compensated view prediction, our proposed triangular mesh representation of the depth data is a natural fit for modern graphics architectures.