Algorithm To Embed Multiple Digital Watermarking In BMP Image

In recent years, Digital Watermarking technology research has aroused wide concern. However, few people have mentioned Multiple Watermark. Multiple Watermarking technology is used to solve many copyright issues and digital products in the publication, sale, and different using stages of the certification rights. Compared to single watermark, Multiple Watermarking signal's generation and the algorithms to embed watermark signal has more requests. For example, the watermark signal must meet the formation of simple, and the large number of Multiple Watermarking signals should unrelated, Moreover, how to keep the Multiple Watermark signal transparency and its robustness is more complex. Among all these questions, the most important one is how to ensure several watermark signals embedded into the same carrier has no impact on each other. Taking into account the rapid development of digital products and the growing demand of copyright protection, it is necessary to study multiple watermark embedded algorithm and how the embedded watermark signals have mutual influence between each other. BMP image is a popular image coding method used epidemically recently. Hence, it's a typical representative of significance for this paper to select BMP images as the carrier of multiple watermarking.In this paper, we propose a useful method to embedded Multiple Watermark into the carrier. Firstly, we use orthogonal sequence to merger several watermark signal into one signal, then we embedded the combination signal into the image carrier. Since the orthogonal sequence is a great autocorrelation and zero cross correlation sequence, we can assure the confidentiality and fault-tolerance of the multiple watermark signals; The next step is to use interleave to make the multiple watermark signal intertwined, in this stage, how many watermark signals the image carrier can carry and fault-tolerance were discussed; If we use the intertwined matrix as a key dimensions, the attacker would not aware of encryption keys under the right circumstances for Multiple Watermarking decomposition will encounter the Factorization difficulty, so the conclusion is that the intertwined watermark signal almost impossible deciphered; Finally, the watermark signal superimposed on the image wavelet decomposition of low-frequency coefficients, so do the watermark embedded in the signal extraction and Noninterference can also prevent malicious watermark signals are removed, thus, the security of the watermark signal were enhanced. To further enhance performance and considering the localization character of wavelet transform in spatial domain, a block-based rounding method is adopted to achieve the purpose of precise embedding. As to the detecting algorithm, a novel difference detecting algorithm is created to improve the robustness of system. As a prerequisite for no judgment, we can achieve multiple watermark detection signals blindly.The research work and results of this paper were relying on a major key project in Shanghai Science and Technology Commission, we proposed an algorithm to integrate multiple orthogonal sequence information into multiple watermarking. On this base, we apply the algorithm to mobile security coupons system, the main application were two special photos: Long-pei pictures and PDF417 photo, and the experiment has produced good results.