METHOD AND APPARATUS FOR DETECTING CORRELATION BETWEEN A RECEIVED SIGNAL AND A CANDIDATE SPREADING SEQUENCE

摘要

Audio watermarking technologies use correlation to retrieve the watermark data. The inventive method for detecting correlation between audio signals includes the steps of calculating the absolute values of the correlated signals, lowpass filtering these absolute values, evaluating the correlation in two different time ranges, namely one where the direct sound is expected and the other where the first echo is expected, calculating the maxima in both ranges, and choosing the correct correlation from several candidate correlations based on these maxima.