High Fidelity Compression of Irregularly Sampled Height-Fields

This paper presents a method to compress irregularly sampled height-fields based on a multi-resolution framework. Unlike  many other height-field compression techniques, no resampling is required so the original height-field data is recovered (less quantization error). The method decomposes the compression task into two complementary phases: an in-plane compression scheme for (x, y) coordinate positions, and a separate multi-resolution z compression step. This decoupling allows subsequent improvements in either phase to be seamlessly integrated and also allows for independent control of bit-rates in the decoupled dimensions, should this be desired. Results are presented for a number of height-field sample sets quantized to 12 bits for each of x and y, and 10 bits for z . Total lossless encoded data sizes range from 11 to 24 bits per point, with z bit-rates lying in the range 2.9 to 8.1 bits per z coordinate. Lossy z bit-rates (we do not lossily encode x and y) lie in the range 0.7 to 5.9 bits per z coordinate, with a worst-case root-mean-squared (RMS) error of less than 1.7% of the z range. Even with aggressive lossy encoding, at least 40% of the point samples are perfectly reconstructed.