| US 7,571,316 B2 | ||
| Method and device for transforming a digital signal | ||
| Patrice Onno, Rennes (France); and Fabrice Le Leannec, Cesson Sevigne (France) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Jul. 18, 2003, as Appl. No. 10/621,418. | ||
| Claims priority of application No. 02 09134 (FR), filed on Jul. 18, 2002. | ||
| Prior Publication US 2004/0042486 A1, Mar. 04, 2004 | ||
| Int. Cl. H04L 9/00 (2006.01) | ||
| U.S. Cl. 713—160 [380/269; 370/466; 725/31] | 30 Claims |
| 1. A method of scrambling a digital signal, comprising the steps of:
decomposing the digital signal into a plurality of regions, each region containing digital data;
encoding the digital signal in a format comprising header data specific to each region, the header data including a parameter
representing a number of bitplanes of samples of a corresponding region; and
modifying the parameter to cause an erroneous value of an amplitude of the samples, thereby causing the digital signal to
be degraded,
wherein the digital data of the digital signal are digital samples representing physical quantities, and
wherein the number of bitplanes includes a number of zero bitplanes and a number of non-zero bitplanes, and the number of
bitplanes are encoded based on the difference between (1) a number of reference bitplanes and (2) the number of zero bitplanes.
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