Patent ID: 8194803

Claim:
Method for regaining watermark data that were embedded in an original signal by modifying sections of said original signal in relation to at least two different reference data sequences, wherein a modified signal section is denoted as ‘marked’ and an original signal section is denoted as ‘non-marked’, said method including the steps: correlating in each case a current section of a received version of said watermarked signal with candidates of said reference data sequences, wherein said received watermarked signal can include noise and/or echoes; based on the correlation result values for said current signal section, optionally determining whether said current signal section is non-marked and if not true, carrying out the following steps; determining for each one of said candidate reference data sequences, based on two or more significant peaks in said correlation result values, the false positive probability, wherein said false positive probability is derived from the probability density function of the amplitudes of the correlation result for a non-marked signal section and from a first threshold value related to said probability density function; selecting for said current signal section that one of said candidate reference data sequences which has the lowest false positive probability, in order to provide said watermark data.