| US 7,580,578 B1 | ||
| Method and device for forming a compressed transcoded digital image signal | ||
| Patrice Onno, Rennes (France); Fabrice Le Leannec, Cesson Sevigne (France); and Raphaël Grosbois, Lausanne (Switzerland) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Feb. 03, 2004, as Appl. No. 10/769,769. | ||
| Claims priority of application No. 03 01224 (FR), filed on Feb. 03, 2003; and application No. 03 04454 (FR), filed on Apr. 10, 2003. | ||
| Int. Cl. G06K 9/36 (2006.01) | ||
| U.S. Cl. 382—232 [382/248] | 17 Claims |
| 1. A method of forming a compressed transcoded digital image signal from a compressed original digital image signal which
comprises digital data organized in blocks, the compression of the original signal comprising at least one step of spatio-frequency
transformation of the original signal and a step of coding the data blocks of said transformed signal,
said method using a processor to perform the steps of:
selecting a data block in one of the compressed signals between the compressed transcoded digital image signal and the compressed
original digital image signal, said selecting comprising identifying the spatial position of said data block in the selected
compressed signal,
identifying, in the non selected compressed signal, the spatial position of a dual data block which corresponds to the data
block selected having regard to a given geometric transformation applied to this block,
decoding the data block belonging to the compressed original signal,
applying the given geometric transformation to the data block thus decoded,
coding the geometrically transformed data block, and
inserting the first data block thus coded in the compressed transcoded image signal at the position of its dual block.
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