Method and apparatus for correlating two data sections

Abstract

Watermarking of audio signals intends to manipulate the audio signal in a way that the changes in the audio content cannot be recognised by the human auditory system. The watermark data are decoded from the received watermarked audio signal by correlation with corresponding candidate reference sequences. One or more of the sync symbols (S1, S2, S3) are embedded twice in the watermark data frame in the encoder. Thereafter a circular correlation is calculated instead of a standard correlation.

Description

technical field [0001] The invention relates to a method and a device for correlating two data segments. This correlation can be used in audio watermark decoding. Background technique [0002] Watermarking an audio signal is to process the audio signal in such a way that changes in the audio content are not discernible by the human auditory system. Most audio watermarking techniques add a spread spectrum signal covering the entire frequency spectrum of the audio signal to the original audio signal, or insert one or more carrier waves modulated with the spread spectrum signal into the original audio signal. To a more or less audible degree, and in a more or less robust manner, there are several possibilities for watermarking. The current state of the art uses psychoacoustic shaped spread spectrum techniques, see eg WO-A-97 / 33391 and US-A-6061793. Although the robustness of this technique is suboptimal, the technique provides a good compromise between audibility and robustn...

AI Technical Summary

Problems solved by technology

Although the robustness of the technique is suboptimal, the technique provides a good compromise between audibility and robustness

Images