Research And Application Of Digital Watermarking For Document Image

With great development of the network technology, the protection of multimedia is more and more important, and the information hiding technology developed. After many years of development, the study of protection for digital image is mature, but what can't ignore is: In fact, lots of important documents, such as digital book, archives, are kept in document image form, they also need copyright protection. So the valuable research of document image is very important.In recent years, either inside or outside nation, there is a great progress in watermarking method research, but the technique research aiming at Binary Images is limited. Because of the specialty of Binary Images itself, the Binary Images watermarking have big difference to the common watermarking, the date hiding methods which is used in gray image and color image is hard to be used in Binary Images. In this paper, by analyzing the characteristic of Chinese character, a new and handy watermarking solution which is use in Chinese character image is proposed. That is based on crossing characteristics of horizontal stroke and orthogonal stroke in Chinese which named"Inflexion", and analyses several advantages over the conventional text watermarking algorithms absolutely based on format of text documents.The major research works and innovatory points in this thesis are as follows:1. Investigate the basic principles and characteristic of digital watermarking technique,introduce the research backgrounds, basic principles, application areas, and recent development and the future of the digital watermarking technology.2. This paper introduces presently the research of text watermarking technology, and analyses typical algorithms aimed at varies of classification methods.3. Mainly studies the preprocess technology about our algorithm, including binarization, denoising, undoing rotation and segment.4. This paper analyzes the representative digital watermarking schemes about document image, and then introduces a new document image watermarking schemes according to an architectural feature of Chinese characters and DRDM measure. The application of proposed watermarking algorithm is studied with MatLab. The experimental results show that the watermarks are invisible and robust against noise and commonly used image-processing methods such as Guassian, Salt, Pepper noise, JPEG, crop procession etc. The algorithm offers a feasible method to protect and authenticate the binary texts such as check, bargain, certificate, ID (identification) and other valuable documents.5. The research direction and possible prospect of the digital watermarking for Chinese text document s are analyzed.