Research On Blind Identification Algorithm Of Digital Watermark Tamper

In the era of rapid development of information technology,digital media technology and computer network technology.The Internet makes it more convenient and fast for people to transmit data.As a result,more and more security risks appear in the process of data transmission.As an important and effective means of digital information copyright protection in the field of modern information security,digital watermarking technology is used to prove the copyright of digital products,the integrity of digital products,track piracy or provide additional information of products.An ideal watermarking algorithm should not only be able to hide a large amount of data,but also be able to resist all kinds of channel noise and signal distortion.In reality,these two indicators are contradictory to each other,which is difficult to realize at the same time,and there is a lack of judgment on tampering in the transmission process.In this paper algorithm is designed from two aspects of the watermark image scrambling algorithm and watermark embedding algorithm Firstly,the tamper bits are highly scattered so that the information contained in the watermark is tampered with as little as possible.In the second step,double watermarking algorithm is designed.In this paper,the embedding design is carried out in gray scale and color space respectively.While ensuring high security,transparency and robustness of watermark images,the tampering method is blind recognized by the embedded recognition factor.In this paper,the main work is illustrated as follows:1.Based on the research of the watermark scrambling preprocessing algorithm,two kinds of scrambling algorithms which can be applied to any size image and can be restored without the original image after simultaneous scrambling are selected.It is design by combining that word Z scan algorithm and the affine scrambling algorithm.By changing the cycle and combination mode of the scrambling operator,a scrambling preprocessing algorithm with the highest tamper bit dispersion is obtained.The dispersion of tamper bits is enhanced in order to enhance the robustness and the anti-tamper ability of watermark image improving.It provides a preprocessing algorithm for tamper blind recognition and embedding of watermark.2.Design a double-watermarking algorithm for blind recognition of tampering with digital watermarks based on gray scale images.Firstly,discrete wavelet transform is used to embed the scrambled watermark image which has stronger robustness.Next discrete cosine transform is used to embed a fragile recognition factor.The embedding of watermark and recognition factor is designed to realize blind extraction without original image in the process of watermark and recognition factor extraction.This paper studies the recognition factors extracted after tampering with different tampering methods,judges the recognition factors with different characteristics corresponding to different tampering methods,and realizes blind recognition of tampering with watermarks.3.Embed color watermark images based on color YIQ space.Firstly,the characteristics of YIQ color spatial decomposition of images were studied? And the color watermarking algorithm was studied and designed to realize the color watermark image without blind extraction of the original image with good robustness.Discrete wavelet transform is used to embed watermark image with good robustness,and discrete cosine transform is used to embed recognition factor.To study the robustness of color image tampering to extract watermark image and the change of color and gray image information of recognition factors for different tampering methods.In this paper the watermark image is extracted with good robustness and the tampering mode is recognized blind.