Method of detecting a watermark in an information signal, software watermark detector to detect a watermark in an information signal, and apparatus for presenting an information signal

摘要

Method of detecting a watermark in an information signal, software watermark detector to detect a watermark in an information signal, and apparatus for presenting an information signal, a detector (100) detects the presence of a watermark in an information signal Tion.The information signal is correlated with an expected watermark (WI) for each of a plurality of positions of the information signal with respect to the watermark to derive a set of correlation results (64). A metric, such as a square average value is calculated for a group of results (64).The metric is compared with a threshold value H that is indicative of the presence of a group representing the peak of correlation. The metric can be calculated for clusters formed the all position results in the temporary memory (64). Alternatively, the metric can be calculated only for a group that is identified as being a peak correlation likely.