Electronic watermark embedding apparatus and method and electronic watermark examining apparatus and method
US7881492B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 14, 2007 |
| Grant date | Feb 1, 2011 |
| Priority date | — |
| Expiry date | Dec 14, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/32192
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electronic watermark embedding apparatus includes means for storing a pixel matrix G with n rows and n columns of an input image, means for acquiring eigenvalues s1 to sn and eigenvectors p1 to pn of the pixel matrix G, means for selecting at least one pair of eigenvalues (si,sj) having different values from the eigenvalues s1 to sn and correcting the eigenvalues s1 to sn such that the values of the selected pair can be equal, means for creating a Jordan-normal-form matrix Sw having the corrected eigenvalues as diagonal elements and 1 as one of the nondiagonal elements corresponding to the selected pair, means for outputting the eigenvectors p1 to pn as electronic watermark key information, means for performing the inverse transform of diagonalization computing on the created matrix Sw by using the eigenvectors p1 to pn to create a pixel matrix Gw with n rows and n columns thereby and outputting it as an electronic-watermark-embedded image of the input image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.