Improved coding of atoms in matching pursuits

An improved method is presented for coding the atoms found by the matching pursuits algorithm used in compressing displaced frame difference (DFD) images in motion compensated video coding. A list of atoms is collected, which are then communicated in the order of their most significant bit plane, rather than being communicated as they are found. The atom positions are run length coded, with the sign, extra bits of magnitude and code-book entry sent as side information. The magnitudes are represented by the most significant bit plus a specified number of additional bits. The distortion is never worse than the standard coding method, and can be up to 1dB better. The magnitude precision for best PSNR is found to be 2 at low bit rates and 1 at high bit rates in the examples considered.