| 摘要 |
The invention relates to a method for embedding and detecting a watermark in a digital audio signal. For embedding the watermark in the digital audio signal a modified-segment (S<SUB>out</SUB><SUP>(t)</SUP>) is created from a selected input-segment (s<SUB>in</SUB><SUP>(t)</SUP>) of the digital audio signal. The modified-segment (s<SUB>out</SUB><SUP>(t)</SUP>) is created such, that at least one of two sub-segments ((s<SUB>sub</SUB> , 1 <SUP>(t)</SUP>(s<SUB>sub</SUB> , 2 <SUP>(t)</SUP>) of the input-segment (s<SUB>in</SUB><SUP>(t)</SUP>) is time-shifted (dt) such that in an overlapping zone (L<SUB>ov</SUB>) a correlation value of the two sub-segments (s<SUB>sub</SUB> , 1 <SUP>(t)</SUP>, (s<SUB>sub</SUB> , 2 <SUP>(t)</SUP>) is a maximum. The signal (s<SUB>ov</SUB>(t)) in the overlapping zone (L<SUB>ov</SUB>) is then created as a weighted average of the two sub-segments ((s<SUB>sub</SUB> , 1 <SUP>(t)</SUP>, (s<SUB>sub</SUB> , 2 <SUP>(t)</SUP>) in said overlapping zone. For detecting the embedded watermark in a received digital audio signal (x(t)), a first template-signal (h1 (t)) and a second template-signal (h2(t)) are generated. Then a first (c1) and a second (c2) correlation value are created by comparing the first (h1(t)) and second (h2(t)) template-signal with the received digital audio signal (x(t)). Finally, it is assumed that a watermark is included in the received digital audio signal, if the second correlation value (c2) is higher than the first correlation value (c1). |
