METHOD OF EMBEDDING AND DETECTING WATERMARK USING LINEARITY OF DISCRETE COSINE TRANSFORMATION

摘要

PURPOSE: A watermark inserting and detecting method using linearity of DCT(Discrete Cosine Transformation) is provided to control DCT coefficients in a spatial area by using linearity of DCT for semi-fragile watermarking, thereby quickly inserting a watermark with a small number of calculations and controlling desired DCT coefficients only. CONSTITUTION: By dividing original image data(500), spatial image data is produced(502). Based on a PN sequence and the divided spatial image data, a watermark inserting position and an amount of insertion are determined(512). By reading data for adding(504), the data is multiplied with the determined amount of insertion, to generate data added as much as the amount of the insertion(506). When watermark information is inserted into an original image, the image inserted with the watermark information is completed(508).