RANDM: Random Access Depth Map Compression Using Range-Partitioning and Global Dictionary

We present a novel random-access depth map compression algorithm (RANDM) for interactive rendering. Our compressed representation provides random access to the depth values and enables real-time parallel decompression on commodity hardware. Our method partitions the depth range captured in a given scene into equal-sized intervals and uses this partition to generate three separate components that exhibit higher coherence. Each of these components is processed independently to generate the compressed stream. Our decompression algorithm is simple and performs prefix-sum computations while also decoding the entropy compressed blocks. We have evaluated the performance on large databases on depth maps and obtain a compression ratio of 20 − 100 × with a root-means-square (RMS) error of 0.05 − 2 in the disparity values of the depth map. The decompression algorithm is fast and takes about 1 microsecond per block on a single thread on an Intel Xeon CPU. To the best of our knowledge, RANDM is the first depth map compression algorithm that provides random access capability for interactive applications.