| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method and apparatus for accurately detecting watermark information weakened by the attack of scaling or rotation or the like not attended with an increase in a computing amount and a circuit scale. <P>SOLUTION: This electronic watermark detecting apparatus is configured such that a particular frequency component extracting unit 11 employing a HPF or a BPF extracts a particular frequency component signal from an input image signal 10, a phase converter 12 applies phase conversion (phase shift) to the particular frequency component signal, a correlation arithmetic unit 13 applies a correlation arithmetic operation to the particular frequency component signal after the phase conversion and the input image signal 10, and a watermark information estimate unit 14 detects the watermark information embedded in the input image signal 10 on the basis of the result of the correlation arithmetic operation. <P>COPYRIGHT: (C)2004,JPO</p> |
