Compression of lightfield rendered images using coset codes
Image-based rendering (IBR) and lightfield rendering (LFR) techniques aim to represent a 3D real-world environment by densely sampling it through a set of fixed viewpoint cameras. Remote digital walkthroughs of the 3D environment are facilitated by synthesizing novel viewpoints from the captured view-set. The large amount of data generated by the dense capture process makes the use of compression imperative for practical IBR/LFR systems. In the present paper, we consider the design of compression techniques for streaming of IBR data to remote viewers. The key constraints that a compression algorithm for IBR streaming is required to satisfy, are those of random access for interactivity, and precompression. We propose a compression algorithm based on the use of coset codes for this purpose. The proposed algorithm employs H.264 source compression in conjunction with LDPC coset codes to precompress the IBR data. Appropriate coset information is transmitted to the remote viewers to allow interactive view generation. Results indicate that the proposed compression algorithm provides good compression efficiency, while allowing client interactivity and server precompression.