Information Hiding Technique Research Based On Grey Theory In Dct Domain

Information hiding technique has increasingly been a hotspot in information security fieldas well as Internet development and communication security requirements. Its one of mainresearch objects is static image, which is one of the multiple net digital media. Grey theory hasbeen widely applied in image operation, though is a new rising theory. Thus, combining withGrey Theory, this thesis explores a new information technique. Its main contents and innovationssummarized as follows:1．Emphatically researched on Grey Relational Analysis. Its main method, means, feasibleapplications and key problems in image operations has been detailedly introduced, thus toprepare for designing new information hiding algorithms based on Grey Theory in sequence.2．Designed a new information hiding algorithm based on Grey Theory with grayscale imagein DCT domain. Firstly, embed areas are of related complex textures choose from image by GreyRelational Analysis. Secondly, embed positions are selected from intermediate frequencycoefficients after embed areas been DCT transformed. Thirdly, embed intensity is flexiblycoordinated with HVS visual sensitivity in DCT domain. Finally, secret information is hidden inselected embed areas with flexible embed intensity. Results of experiments show this methodsatisfies sightless and robustness.3．Designed a new blind information hiding algorithm based on Grey Theory with colorimage in DCT domain. This method is mainly combined with two principles: the grey rule asnature color images are commonly followed and one characteristic of grey relational measureadvanced by Mr. Deng. Firstly, the source color image is blocked by 8×8. Then, R, G,.B pixelsof every block is DCT transformed. Secondly, the grey relational degrees of R, G, B DCTcoefficients are calculated with reference sequence. Thus embed areas are choose form thoseblocks which R, G, B grey relational degrees are smaller than a certain value. Thirdly, embedpositions are choose from DCT middle near high frequency coefficients. Finally, secretinformation embed in embed positions by only exchanging the neighbor coefficients, andsubstitute the origin coefficients to make the color image carried with secret information. Resultsof experiments show that this algorithm can make secret information hidden sightless and resiston some common attacks.Finally, It is summarized, and the information hiding technique research based on GreyTheory is prospected.