| United States Patent | 7,486,212 |
| Chen , et al. | January 27, 2009 |
Variable length coding for sparse coefficients
Abstract
Coding quantized transform coefficients as occur in image compression includes, for a subset of coefficient amplitude values coding by a first method corresponding to each amplitude of the subset, events of a run of zero or more zero-valued coefficients ending in the single non-zero amplitude, coding by a second method events of a run of zero or more zero-valued coefficients ending in any single non-zero amplitude not in the subset, and coding by a third method the amplitude values of the concatenation of the non-zero amplitude not in the subset. The coding methods produce variable length codewords. The method is suitable for series that have scattered non-zero-valued coefficients.
| Inventors: | Chen; Wen-hsiung (Sunnyvale, CA), Toebes; John A. (Cary, NC) |
| Assignee: | Cisco Technology, Inc. (San Jose, CA) |
| Appl. No.: | 11/761,307 |
| Filed: | June 11, 2007 |