An Algorithm Of Digital Watermarking Based On Wavelet Domain And Color Images

With the development of technology, in order to better protect the interests of propertyrights, intellectual property rights system came into being and constantly improving. However,more and more threats appear to the copyright owner due to digital information processing,dissemination of the special nature of digital information. With the growing concern in thisrespect, the protection of digital information has been changed from the original encryptiontechnology to hide into a new information technology-digital watermark technology. It isdifferent from traditional encryption technology, not information into cipher text form ofcommunication, it is mainly characterized by hidden information, certain information will behidden in another public information among the public of information to pass through thehidden information. Digital watermark is generated in this context an emerging field, andbecome a new kind of intellectual property protection of digital information technology.Current digital watermarking for grayscale images from the early development ofalgorithms to color images, this wavelet-based color image watermarking algorithm research,design a kind of wavelet-based color image watermarking algorithm. The algorithm uses theYCbCr color model, the original color image to extract the luminance component Y, with thehuman visual system (Human Visual System), through the image is too dark out and thesensitivity of the area derived from the visual JND threshold model, then the wavelettransform; luminance component Y and then the wavelet transform of each sub-layer bandhorizontal, vertical, diagonal coefficients, arranged in order of size, and the subtraction, thevalue based on features, after subtracting the watermarked image wavelet coefficients; finalthe integration of the grayscale watermark image wavelet coefficients of color images for theluminance component Y wavelet transform, then the original image with the Cb and Crcomponents of reconstruction, has finally been watermarked color image. In other words, usevisual models to determine the modulation associated with the image mask, and then use it toinsert a watermark. Experiment also proved that the method has good transparency androbustness, and watermark invisibility. The improved JND threshold, can effectively ensurethe robustness of the watermark can be effective against a variety of color images for theattacks, the digital color image watermarking applications is important. However, due to the watermark extraction process to use to the original image, the embedded algorithm forgeometric attacks against relatively weak, when there is a large disturbance, the wavelettransform coefficients corresponding to a greater change, which is the paper testUnfortunately, the lack of method in point.At present, the research for color image watermarking algorithm is an emerging area, andthe algorithms is limited, so there is too much room for development for wavelet-based colorimage watermarking algorithm.