The Watermarking For Text Images Based On Arnold Scrambling And Transform Domain

With the continued development of multimedia technology and digital image processing, digital imaging technology has been widely penetrated in every field. Most work focuses on audio, video, grayscale, and color images. In practical application, binary images are very useful for security records, insurance information, financial document, fax images, case history, contract, e-business, e-Government, etc. However, when the text data stores and transmits in the network, is would be attacked easily, which results in low security. As an effective method to protect copyright of digital media, digital watermarking technology has been attached great importance to scholars and research institutions. Digital text watermarking becomes a research hotspot in recent years. This paper describes theresearch background, research status, basic knowledge, typical algorithms, common mathematical transformation, text pre-processing technology of the digital watermarking. This paper proposes robust text watermarking algorithms based on transform domain and compressed domain. The main research contents are as follows:(1) A preprocessing approach is proposed in this paper. The original watermarking is preprocessed using the Arnold scrambling, in order to improve the effect of encryption, the algorithms are optimized in the course of the research on Arnold scrambling.(2) A robust watermarking algorithm for text image on Arnold Scrambling and transform domain is proposed in this paper. This algorithm is combine the scrambled watermarking and the visual feature vector of text images, and then use the sequence as a key through the HASH function. The watermarking is extracted without original text, so the watermarking algorithm is a blind extraction algorithm. The watermarking information dose not been embedded into the text, so it is also a zero-watermarking algorithm. The algorithm combines text feature vector, the third party concept and zero-watermarking together. Simulation results show that the text watermarking algorithm can resist conventional attacks and geometric attacks, which has strong robustness.In summary, some creative watermarking algorithms for text image are studied in this dissertation. Details of the three text watermarking algorithm based on transform domain (DCT, DFT, DWT-DFT) and Arnold Scrambling. Through a series of attacks text image processing, all of the text images reflects the good robustness. In the study of the text watermark indicates another direction. Confirmed the algorithm has quickly computing speed, high precision, good compatibility, strong ability to against the attacks etc. At last, the experiments prove the algorithm’s security.