Method and apparatus for determining and using the sampling frequency for decoding watermark information embedded in a received signal sampled with an original sampling frequency at encoder side

US8688993B2 · kind B2 · utility

Assignee

• Thomson Licensing · FR

Inventors

• Peter Georg Baum · Hannover, DE
• Walter Voessing · Hannover, DE
• Ulrich Gries · Hamburg, DE

Key dates

• Filing date: Jan 6, 2009
• Grant date: Apr 1, 2014
• Expiry date: Jun 30, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N7/167
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

In watermarked signal decoding, the embedded message is decoded by correlating the reference patterns with the watermarked signal. The watermark detector decides, depending on the size of the correlation result values, whether or not a given reference pattern was embedded. However, decoding watermarked audio or video signals is difficult if the link between the watermark encoder and the watermark decoder is not a digital one, for example an acoustic path. A re-sampler control unit controls the sampling frequency of a re-sampler, in connection with a watermark decoder that outputs, in addition to the watermark information bits, a corresponding confidence value that is derived from the correlation result and that is used for synchronizing the re-sampler sampling frequency with the original sampling frequency of the watermarked signal. The synchronization processing includes a search mode and a synchronized mode.