APPARATUS AND METHOD FOR EMBEDDING AND EXTRACTING INFORMATION IN ANALOG SIGNALS USING DISTRIBUTED SIGNAL FEATURES AND REPLICA MODULATION
Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of predefined quantization values corresponding to an information symbol to be encoded. The amount of change required to modify the signal feature to the determined target quantization value is calculated and the cover signal is modified accordingly to so change the feature value over a predefined interval. Information symbols are extracted by the opposite process. In one embodiment, the predefined value is a short term autocorrelation value of the cover signal.
1 . An apparatus, comprising:
a comparator configured to compare a host content with a predetermined auxiliary information carrier, wherein the auxiliary information carrier is based on predefined attributes of the host content and comprises a plurality of components having varying amounts of delay or offset from each other;
a correlator configured to correlate the host signal with a particular component of the auxiliary information carrier, and
an extractor configured to determine a value of an embedded information symbol as a function of a value of the correlated component and a predefined relationship between information symbol values and components of the auxiliary information carrier.
2 . The apparatus of claim 1 , wherein the value of the embedded information symbol enables identification of an attribute of the host content.
3 . The apparatus of claim 2 , wherein the attribute comprises copy management rules associated with the host content.
4 . The apparatus of claim 2 , wherein the attribute comprises usage control rules associated with the host content.
5 . The apparatus of claim 2 , wherein the attribute comprises distribution control rules associated with the host content.
6 . A non-transitory computer-readable storage medium with a host content embodied thereupon, the host content comprising:
one or more auxiliary information symbols that are imperceptibly embedded in the host content, wherein reception of the host content at a content handling device equipped with a watermark extractor triggers the watermark extractor to:
compare the host content with a predetermined auxiliary information carrier, wherein the auxiliary information carrier is based on predefined attributes of the host content and comprises a plurality of components having varying amounts of delay or offset from each other;
correlate the host signal with a particular signal component of the auxiliary information carrier; and
determine a value of an embedded information symbol as a function of the value of the correlated component and a predefined relationship between information symbol values and components of the auxiliary information carrier.