Digital Image Watermarking Algorithm Based On Multi-scale Technology

Digital watermark is a novel technique for protecting intellectual property rights. The copyright information-digital watermark is embedded into digital products to verify their ownerships. The embedded watermark information is usually invisible or imperceptible. However, a detector can be used to extract it or determine its existence. Recently, this technique has become a hot spot in research of multimedia information security.This paper addresses research of image digital watermark algorithm.The main tasks are summarized as follows:1. Both chaos and scramble theories are studied and the simulations are also implemented by the computer.2. Design a digital watermark algorithm based on discrete wavelet transform by making full use of human visual properties. Firstly the digital watermarking is randomly scrambled by Arnold transformation. Then the chaotic watermarking is inserted to the low-frequency coefficients in the discrete wavelet domain. Watermarked image is obtained by inverse discrete wavelet transformation. Then the image is decomposed by three-level discrete wavelet transformation, and the watermarking is extracted through a certain way. Finally the primitive watermarking is obtained by anti-Arnold transformation.3. A new kind of watermark-inserting and extracting algorithm based on discrete stationary wavelet transform is proposed. Firstly the digital watermarking was randomly scrambled by the Arnold transformation. Then the chaotic watermarking is inserted to the low-frequency coefficients in the discrete stationary wavelet domain.. Watermarked image is obtained by inverse discrete stationary wavelet transformation. Then the watermarked image is decomposed by discrete stationary wavelet transformation. And the watermarking is extracted through a certain way. Finally the primitive watermarking is obtained by chaotic decryption and anti-Arnold transformation.4. A digital watermark embedding and extracting algorithm is proposed by discrete curvelet transform and genetic algorithm. First, this algorithm decomposes an original image into threelevels, and get a rough yardstick coefficient matrix. Then genetic algorithm is used to find the optimal location to embed watermarking information. Finally, watermarking information is inserted to the rough yardstick coefficient matrix. The watermarked image is obtained by inverse curvelet transform. Accoring to the chromosome preservated in genetic algorithm, and the gray matrix of watermarking is calculated.The experimental results show that it is better robustness to some attacks, such as compression, rotation, shearing, filtering, sharpening, noise, and so on.