Watermark detection

Abstract

A detector (100) detects the presence of a watermark in an information signal. The information signal is correlated with an expected watermark (Wi) for each of a plurality of relative positions of the information signal with respect to the watermark to derive a set of correlation results (64). A metric, such as a mean square value, is calculated for a cluster of the results (64). The metric is compared with a threshold h which is indicative of the cluster representing the presence of a correlation peak. The metric can be calculated for clusters formed at every position in the results buffer (64). Alternatively, the metric can be calculated only for a cluster which is identified as being a likely correlation peak.

Dependencies are inferred from the claim text.