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Research Of Image Digital Watermarking Based On Various Transform Domain

Posted on:2006-01-21Degree:MasterType:Thesis
Country:ChinaCandidate:X C QiFull Text:PDF
GTID:2168360155468525Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
With the rapid growth of Internet technologies and extensive use of multimedia data, digital watermark has become a popular topic in the field of digital copyright protection. Digital watermark serves as protecting the securities of digital multimedia by embedding special information into it.This paper is focused on images watermarking algorithm, It developed mainly in the follow aspects:1. This paper is focused on images watermarking algorithms. Watermark casting operates in frequency domain, embeds pseudo-random sequence of real number in selected coefficients without image degradation. A blind watermark retrieval technique that can detect the embedded watermark without resorting the original image is proposed, so that the proposed techniques represents a major improvements to those relying on the comparison between the watermarked and original image, which is not practical for a huge image database. All process, include watermark embedding, extracting and verification are simulated in MATLAB environments. Experimental results show that the embedded watermark is robust against various signal processing and compression attacks.2. This paper analyzed the frequency domain watermark algorithm. Embedded the watermark information into intermediate frequency in the DCT based watermark algorithm. This paper chose lifting scheme and Daubechies9/7 function to finish wavelet transform. In DWT base system, a couple of significant wavelet coefficients in detailed sub-bands are selected to embed watermarks by first level decomposing. A better image quality (imperceptibility) can be gained by exploiting human visual system. Compared with DCT based system, DWT base watermark system is an adaptive system. As the multi-resolution property of DWT enable DWT basedwatermark system combine the statistic characteristic of image with humanvisual system, make it possible to find an optimal system. 3. Using proposed system test the parameters which work on the systemperformance, such as embed position, embed strength, watermark structure,image capacity and HVS etc.
Keywords/Search Tags:digital watermark, discrete cosine transform, discrete wavelet transform, lifting scheme, multi-resolution analysis
PDF Full Text Request
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