Digital Watermarking Algorithm And Implementation

The Research and Implementation of Digital Watermarking AlgorithmNetwork has become a indispensable part in people's daily life. Data transmission, copy, delete and other operations which were accompanied by network technology unceasing progress are becoming more quick and easier to operate. In order to seek personal interests fully utilize the convenience of network technology, illegal elements make some illegal operators, such as copying and spreading the data without the authorization of the copyright. The traditional law and management methods have not solved the problem yet, so we need use some hi-tech means to stop the illegal behavior. Digital watermarking technology is one of the most effective solutions now; it confirms the ownership of the data and information by adding watermark to the original image.This paper detailed introduces the background, significance of the digital watermarking, and the basic models, properties, the basic algorithm and other knowledge of the digital watermarking system. Based on that, this paper intensive study three kinds of digital watermarking algorithm. Then analysis, comparison and innovation, test and verify the merits and demerits of these three algorithms. Mainly includes the following aspects:1.This paper proposed a new digital watermarking algorithm based on the difference value of the image itself. Firstly, the original image is transformed with three levels of wavelet transform. Then take the three high frequency coefficients to zero. After entered wavelet inverter change, we get the wavelet reference images of the original image about their own second wavelet transform. Then compare them with the coefficients of the original second wavelet transform, we get their differences absolute value. By comparing their absolute value, the scrambled watermark image is embedded into the second wavelet transform coefficients through the appropriate intensity. Finally after wavelet inverter change, it gets the watermark image. This algorithm based on extracting itself image differences value method, considered the transform domain method, and solved the lack of robustness problems of the airspace methods.2.This paper proposed a new watermarking algorithm based on Wavelet Transform. First of all, according to the characteristics of color image, the green component of the color image is extracted and then transformed with three levels of wavelet transform.what's more, the scrambled watermark image is embedded to the already sorted wavelet coefficients of maximum coefficient of high frequency sub-bands. Last but least, the JND threshold (Just Noticeable Difference) is calculated to adjust watermark embedding strength. This algorithm can have better robustness and transparency.3.This paper proposed a new digital watermarking algorithm. This algorithm applied iterative blending technology and combined with SVD and DWT. In order to increase the amount of information, this algorithm put gray image as watermark image. First the original image is transformed by three layers of wavelet transform. Then the scrambled grayscale watermark is embedded into the low-frequency coefficients of the third wavelet transform.And the same watermark is embedded into the singular decomposition value of the high frequency coefficients. In embedded process, the watermark information was embedded into image watermark coefficient by the hybrid iterative method. It could prevent image distortion after embedded. This algorithm can resist shear, compression, noise and other attacks. This algorithm has good transparency.