| US 7,613,320 B2 | ||
| Digital watermark embedding apparatus and method, and digital watermark analysis apparatus, method and program | ||
| Hirofumi Muratani, Kawasaki (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Oct. 06, 2008, as Appl. No. 12/246,234. | ||
| Application 12/246234 is a continuation of application No. 10/648522, filed on Aug. 27, 2003, granted, now 7,443,999. | ||
| Claims priority of application No. 2002-248491 (JP), filed on Aug. 28, 2002. | ||
| Prior Publication US 2009/0049304 A1, Feb. 19, 2009 | ||
| Int. Cl. G06K 9/00 (2006.01) | ||
| U.S. Cl. 382—100 | 12 Claims |
| 1. A digital watermark analysis apparatus for specifying at least one of a plurality of identification information items embedded
as a plurality of watermark information items in a plurality of legal copies of digital contents used for collusive attacks,
from a plurality of illegal copies of the digital contents obtained by collusive attacks made against the legal copies, the
digital watermark analysis apparatus comprising:
an extraction unit configured to extract a plurality of embedded codes including ranks from the illegal copies, each of the
ranks being uniquely numbered among each of the embedded codes and extract, in units of ranks, one of the embedded codes which
is estimated to be most frequently used in the collusive attacks;
an acquisition unit configured to acquire a plurality of symbols corresponding to the embedded codes and arrange the symbols
in accordance with the ranks of the embedded codes, and acquire a first symbol sequence of symbol sequences each of which
includes a plurality of the arranged symbols; and
a specifying unit configured to specify at least one of the identification information items embedded in the legal copies,
based on the first symbol sequence and second symbol sequences uniquely assigned to the identification information items.
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