Patent ID: 6785401
Filing Date: 2004-08-31
Classification: G06T

Abstract:
A method of temporally synchronizing a watermark decoder with a watermark encoder comprising the steps of:at the watermark encoder generating a pseudo-noise sequence for a block of signal frames having a duration of N frames at a frame rate of a signal to be watermarked where N is an integer; multiplying a spatial synchronization pattern by the pseudo-noise sequence to produce a spatio-temporal synchronization pattern; adding the spatio-temporal synchronization pattern to a data pattern to produce a watermark pattern for watermarking the signal to produce a watermarked signal; and at the watermark decoder correlating the watermarked signal with the spatial synchronization pattern to produce a temporal synchronization signal; generating from the temporal synchronization signal an offset signal representing a temporal offset between the watermark encoder and watermark decoder; and synchronizing the watermark decoder with the watermark encoder using the offset signal.