Research On Image Watermarking Based On Contourlet Transform

With the multimedia technology, computer networks and communicationtechnology, the rapid development of digital products more and more widely, thesecurity of digital information has become issues of concern, the copyright protection ofdigital products is important. Digital watermarking is permanently embedded in the hostcan be identified with the data of the digital signal or pattern, and do not affect theavailability of host data. Digital information security as an effective means of settlement,industry and academia to become a hot research.This thesis has studied the image watermarking and the Contourlet transformcorrelation theories knowledge, proposed based on the Arnold transform and the Lorenzchaos system’s colored watermark image encryption algorithm and one kind ofContourlet territory energy and the exchange coefficient image watermark algorithm.The prime task includes:1.This thesis gives the color image scrambling definition in the deep research grayimage scrambling, because the Arnold transform has the high scrambling, can resistmany kinds of attacks the characteristics, as well as the Lorenz chaos system has thegreatly strengthened starting value sensitivity and the secure characteristic. The thesisproposed one kind based on the Arnold transform and the Lorenz chaos system’scolored watermark image encryption algorithm. This algorithm uses the Arnoldtransformation as well as the color image scrambling definition, to primitive coloredwatermark information’s R, G, B three components carries on the scrambling separately,and solves the Lorenz chaos system’s dynamic equation, obtains three chaos sequences,according to the above constructs the scrambling index matrix; Then after the Arnoldscrambling’s each color component, uses these three different chaos scramblingsequence to carry on scrambling processing. The simulation experiment result indicatedthat this algorithm has overcome the Arnold transformation and the Lorenz chaossystem’s shortcoming, can resist many kinds of attacks, enables the colored watermarkimage to have the high security.2. This thesis proposed one kind of Contourlet the territory energy and theexchange coefficient image watermark algorithm based on deep researched Contourlettransform elementary theory and analyzed the Contourlet transform ratio the distributedcharacteristic.This algorithm uses the Contourlet conversion characteristics fully, after image dissection energy size choice inserting watermark directional diagram, andthrough exchange coefficient inserting algorithm, watermark information insertingcarrier image. This algorithm uses the Contourlet decomposition carrier image layer,each decomposition direction number and the inserting watermark information choiceinnertube three dense spoons in the digital watermark’s telescopiny, therefore, thisalgorithm also has the high security. The image simulation experiment result indicatedthat this algorithm can resist many kinds of common imagery processings and thegeometric transform attack,such as compressing images, adding salt and pepper noise,adding gaussian noise, Gaussian low-pass filtering, Histogram equalization, lighting upthe image, Image dimming, Changing the contrast and cutting.After these attack’simage, the algorithm also withdraw the complete watermark information.