Based On Digital Image Watermarking In The Transform Domain

In recent years, along with the development of computer and network communication technology, various forms of digital products is open applied and transferred on the internet. Which forms not only brings convenient to people but also brings roumania to illegal molecular, for example, they modify and malicious digital products without the franchisor's permission. Digital watermarking technology is an important means of protection and security authentication, This paper mainly studies some improvement realization based on transform domain, and compare with the original transform domain watermarking algorithm and summarize it. The main work includes the follow points:1. A robust digital watermark arithmetic is proposed based on DCT transformation, we firstly scramble the watermark image, then we transform the watermark image and initial image respectively in block DCT transform, we embed each block of the watermark into four adjacent block carrier image in order to make the embedded watermark have strong robustness. The experiment results prove that the arithmetic is of better robustness and invisibility.2. A digital watermark algorithm based on block of singular value decomposition. firstly using the affine transform and SVD to watermark image, For carrier images, firstly use block SVD, extract the largest singular value in every small block to constitutes a new matrix. Continue to carry on the SVD, embedded the watermarking information singular into the carrier diagonal matrix with different intensity, according to getting a embedded watermark image, then using the inverter method to extract watermark information. The algorithm has fully considered the watermark visibility, insensitivity to disturbance, resist geometric transformation, watermarking embedding quantity information, Therefore embedded watermark to image's singular values has good robustness on geometric robustness.3. Proposed a watermarking algorithm based on block SVD and block DCT. Firstly scrambled the watermarking image with Arnold transform, and give it SVD transform. Second, transfer the carrier image with block SVD, Extracted each first singular value to form a new matrix, will the new matrix block DCT transform, extracted the transform coefficient of the DC component consist a new collection. Then embedded the watermark singular value into DC set by different intensity, last using relevant inverter transform to get the embedded watermark image. This algorithm has better stability and robustness than other algorithm, which integrated the characteristic of the safety of scramble, focus ability of DCT transform, stability of SVD. We can use similarity functions and peak value signal-to-noise ratio as a measure of watermark invisibility and the visual property effect.