Research Of Adaptive Digital Image Watermarking Algorithm Based On Matching DCT Block

With the rapid development of computer soft and hard technology， computermultimedia become more and more diversified and the transmission of multimediainformation become more and more convenient， but the problem of multimedia copyrightprotection created. Digital watermarking technology opens up a new direction for copyrightprotection for multimedia data， content authentication and action tracking.This paper first introduces the background and research status of digital watermarkingtechnology; introduces the basic process， main characteristics， classification and evaluatingalgorithms and attack methods of digital watermarking algorithm. This topic puts forward adigital watermark algorithm based on DCT and Data Matrix， this paper introduces theprinciple of DCT transform and blocking DCT transform which is adopted in this paper，introduces the Data Matrix encoding and decoding process. First of all， process the carrierimage and embedding information by blocking DCT， then matching blocking DCTcoefficients to obtain an optimal matching sequence， watermark. In order to the digitalwatermarking algorithm more robustness， the watermark sequence is processed beforeembedding into carrier image. Because the Data Matrix bar code technology has the verygood error correction， so the article adopted the Data Matrix technique to encode watermarksequence to generate watermark image. At the same time， according to the size of thecarrier， scaling， scrambling and parity is used to process watermark image. Finallywatermark image is embedding into carrier image by LSB algorithm and improved LSBalgorithm respectively，and analyses algorithms’ performance comparison. Also，watermarkimage is embedded into the DCT domain.Finally， the paper summarized the completed work and gave prospects for researchwork next.