Patent ID: 6240121
Filing Date: 2001-05-29
Classification: G06T,H04N

Abstract:
A watermark data insertion method for inserting watermark data into an input original signal, comprising:a frequency transform step of applying a frequency transform to the original signal to form an intermediate signal;a watermark data insertion step of inserting the watermark data into a first set of frequency components of the intermediate signal; anda frequency inverse transform step of applying an inverse frequency transform to the intermediate signal, the watermark data having been inserted into the intermediate signal, thereby obtaining a signal containing the watermark data embedded therein,wherein the watermark data insertion step comprises:determining, based on pseudo random numbers, the first set of frequency components of the intermediate signal into which the watermark data is inserted; andusing a second set of frequency components of the intermediate signal as a reference signal, the watermark data not being inserted into the second set of frequency components.