Apparatus and method for watermark data insertion and apparatus and method for watermark data detection

Abstract

A watermark data insertion method for inserting watermark data into an input original signal is provided. The method includes: a frequency transform step for applying a frequency transform to the original signal to form an intermediate signal; a watermark data insertion step for inserting the watermark data into a first set of frequency component of the intermediate signal; and a frequency inverse transform step for 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. The watermark data insertion step includes: determining, based on pseudo random numbers, the first set of frequency components of the intermediate signal into which the watermark data is inserted; and using 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.

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