The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2007
Filed:
Apr. 23, 2003
Xiaomang Zhang, Tenri, JP;
Akira Yamanishi, Tenri, JP;
Xiaomang Zhang, Tenri, JP;
Akira Yamanishi, Tenri, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
The watermark insertion section divides the quantized DCT coefficients into at least two data streams, and modifies values of AC components of the data streams, so as to embed the watermark information in each block of the image information with the DCT coefficients quantized. The modification is performed as follows. The sum of a plurality of data of each data stream (or the sum of a plurality of data of a prescribed portion of each data stream) is divided by 2. Then, a value of an AC component of each data stream is modified such that the value of each remainder (the value of the LSB) has a prescribed relationship with (for example, is equal to) the value of the watermark information. Specifically, the value of the first non-zero AC component, from the trailing end of each data stream, is processed by addition of 1 or subtraction of 1.