US 6,983,059 B2
Digital watermark detecting device and method thereof
Hirofumi Muratani, Kawasaki (Japan)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan)
Filed on Dec. 07, 2001, as Appl. No. 10/7,769.
Claims priority of application No. 2000-376323 (JP), filed on Dec. 11, 2000.
Prior Publication US 2002/0116618 A1, Aug. 22, 2002
Int. Cl. G06K 9/00 (2006.01)
U.S. Cl. 382—100 19 Claims
OG exemplary drawing
 
1. A digital watermark detecting device comprising:
a sequence generator configured to generate a predetermined sequence of numbers corresponding to a watermark which is to be detected;
a shift circuit configured to shift a detection objective content to obtain shifted content;
a first correlation calculator configured to divide the detection objective content and the shifted content into blocks, and calculate a first correlation value of blocks of the shifted content with the predetermined sequence of numbers and a second correlation value of blocks of the detection objective content with the predetermined sequence of numbers;
a second correlation calculator configured to calculate an estimated correlation value of blocks of an estimated original content in which no watermark is embedded with the predetermined sequence of numbers based on the first correlation value; and
a determination unit configured to determine whether the predetermined sequence of numbers is embedded in the detection objective content based on the estimated correlation value and the second correlation value.