Digital watermark extracting method, apparatus, program and storage medium
US7190807B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2003 |
| Grant date | Mar 13, 2007 |
| Priority date | — |
| Expiry date | May 30, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0083
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention is to precisely extract a digital watermark from image data which are subjected to embedding of the digital watermark in a state of a binary image and are then converted into a multi-value image (gray scale image).For attaining the foregoing object, a digital watermark extracting apparatus for extracting a digital watermark for example in an original includes an acquiring unit for acquiring multi-value image data obtained by reading the original with a predetermined reading unit, a pre-processing unit for selecting one of plural threshold values and binarizing the multi-value image data with the selected threshold value, and an extracting unit for extracting the digital watermark from image data binarized in the pre-processing unit, wherein selection of the threshold value, binarization an extraction of the digital watermark are repeated to obtain an optimum extraction result of the digital watermark.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.