METHOD FOR INSERTING AND EXTRACTING INFORMATION USING DIGITAL WATERMARKING, AND OFF-LINE DETECTING SYSTEM AUTOMATICALLY CORRESPONDING TO ISSUE/DETECTOR AND METHOD THEREOF

摘要

PURPOSE: A method for inserting and extracting information using digital watermarking, and an off-line detecting system automatically corresponding to an issue/detector and a method thereof are provided to increase a detection rate of watermark information in inserting information into all sorts of printed matters and detecting forgery. CONSTITUTION: An information insertion part receives an original copy image(130), information(100) to be inserted, and a user information set(120). The information to be inserted is encoded and error-correction coded. An error detecting code is applied to the information to be inserted and a watermark inserting unit(150) inserts a watermark into the information to be inserted. The original copy image is analyzed related to a frequency domain and is normalized to be a reliable image, having a watermark inserted. The extracted image is corrected. A detection region of the corrected image is extracted to extract information. An error of the data of the extracted region is detected and corrected to increase the accuracy of the information.