직교성분을 갖는 CAT 규칙을 이용한 컬러영상에 디지털 워터마킹 기술

Digital Watermarking Technology for Color Images Using CAT Rules with Orthogonal Components

In this paper, we propose a digital watermarking technology for color images using 2D CAT (Two-Dimensional Cellular Automata Transform) method to prevent image theft and forgery occurring in the process of using color image contents in advance and to protect the author. The proposed method first converts the RGB color region to the YCbCr region. In addition, in order to insert watermark information in the low frequency region, a basis function is generated using the state transition matrix and gateway values for the 2D CAT rule with orthogonal properties. The Y spatial image of the region converted to YCbCr using the generated basis function is divided into low-frequency and high-frequency regions for each group. Watermark information is inserted in the divided low frequency area. After comparing the visual identity with the original image to the image containing watermark information, the PSNR and the normalized correlation coefficient were compared and analyzed. As a result, it was confirmed that there was no difference in the image containing more than 98% watermark information from the original image.