The Research On Print-Scan Resilient Watermarking Algorithms For Digital Raster Binary Map

With the rapid development of e-commerce and e-government,enterprises and institutions,communist party of China and government organs need to deal with a large number of electronic documents,such as contracts,engineering design drawings and so on.Generally,they are in binary form.In addition,in order to facilitate the exchange and sharing of information,many electronic documents have to be printed and copied into paper,and even need to be re-scanned into electronic format to facilitate the transmission on Internet.It is a larger opportunity for criminals to steal and tamper these documents.Therefore,the copyright protection of the digital raster binary image which may be subjected to print-scan operation is a research topic that is the urgent problem to be solved.At present,the research on print-scan resilient watermark algorithm of digital raster binary image is less and it can not be directly applied to digital raster binary image where texture structure is simple and the distribution of black area is uneven.In this paper,the image scrambling is used to solve the problem,and two novel print-scan resilient digital raster binary map watermark algorithms are proposed.Mainly works of this paper include:(1)Print-scan resilient for digital raster binary map watermarking based on extended additive noise model and scrambling is proposed.Firstly,the flipping probability of each pixel is calculated.After that,image is scrambled and partitioned into blocks.Finally,based on extended additive noise model and the number of pixels in block,the watermark information is embedded.Experimental results show that the proposed scheme can not only provide large watermark capacity and good imperceptibility,but also can resist the impact of print-scan on the image,and has strong robustness.Meanwhile,applicable carrier image category is wide.(2)Print-scan resilient for digital raster binary map watermarking based on characteristic value matrix DCT and scrambling is presented.Firstly,the flipping probability of each pixel is calculated,and then the image characteristic value matrix is obtained by scrambling and blocking.Secondly,DCT transform is performed on the characteristic value matrix and the DCT coefficients are modified according to the hidden data.Thirdly,the modified DCT coefficient matrix is used to do the inverse DCT,the pixels being flipped in the corresponding block.Finally,embedded image is obtained by inverse scrambling.Experimental results show that the scheme not only provides larger capacity and better imperceptibility,but also can resists the impact of print-scan,and has strong robustness.Meanwhile,compared with the existing algorithms,it has low implementation complexity and can be applied to military maps,engineering design drawings and other binary images.(3)A set of print-scan resilient watermarking system for digital raster binary map is designed and implemented.The system implements user authentication management module,which is used to verify the legitimacy of users,and the above two methods.The research results can be applied to the safe distribution and copyright protection for paper maps,and provide a new and effective mean for the safety protection of paper maps.It has many richly theoretical and pritical significance.