Application And Research Of Digital Watermarking On Images Copyright Protection

This dissertation mainly studies digital watermarking technology of digital image. Digital watermarking technology is widely studied and applied as an important way to protect copyright by embedding watermark in digital works.This dissertation introduces some digital watermarking classical algorithms and technology after elaborating information hiding theories. At the same time, an adaptive algorithm based on block DCT for digital watermarking are advanced. In this algorithm, a significant watermark or real numbers produced by chaotic system as watermarking signal is embedded in 8 X 8 DCT intermediate frequency coefficient with HVS model as reference. A right conclusion can still drawn by testing chaotic sequence after JPEG compression, HISTEQ and changing the size of an image. A right image watermark can be drawn from image embedded image watermark. Better robustness and right test conclusion are proved by experiment.An image copyright protection system based on the new algorithm is designed and realized. Better stability and robustness of the system are proved by test and the system can meet for special application. Specially, the adoption of chaotic sequence watermark can meet the tremendous demand in the applications and the standardization of watermark signals for its easily producing, large quantity and security. Chaotic watermark signal will help watermarking technology come into realization.