Method and apparatus for determining watermark symbols in a received audio signal that can contain echoes, reverberation and/or noise

摘要

Following transmission of a watermarked audio signal over an acoustic path causing echoes, reverberation and/or noise, watermark detection correlation result peak values are concentrated within a limited temporal range around main correlation result peaks, which limited temporal range is much smaller than the total correlation length. The watermark detection is based on the following: given n_p correlation result peak values v=(v₁, v₂, . . . , v_np) in an average or expected probability distribution for correlation result values for unmarked content, the probability is calculated that within windows covering the limited temporal range there are n_p or more values from a correlation result value set greater than or equal to these peaks v.