| 摘要 |
From sets of correlation result values it is determined whether a specific watermark symbol out of one or more candidate watermark symbols is embedded in a received audio signal. For all candidate watermark symbols, from each corresponding set of correlation result values, a group ( n p ) of maximal values together form a peak vector ( v i ). From the normalised peak values (w i ) a probability distribution function (pdf, g (w i )) and a false positive probability function ( P fp (w i )) are calculated. If the values of the false positive probability function are smaller than a first threshold value (T min ), the current candidate watermark symbol is taken as a true watermark symbol. If not yet all candidate watermark symbols have been processed, the next candidate watermark symbol is selected. Otherwise, a minimal value P f p * of the false positive probability functions for all candidate watermark symbols is determined (76) and is compared (77) with a second threshold value (T max ). If it is smaller than the second threshold value, the current candidate watermark symbol is selected. Otherwise, it is determined (78) that no watermark symbol is present. |
