Research On High-capacity Reversible Data Hiding Algorithm For Color Image

Reversible data hiding technique can not only achieve the purpose of transmitting secret information,but also restore the original cover image without distortion.So it has been widely used and occupies an important place in the organizations that demand for the original cover image is higher,especially in military departments and other institutions.Reversible data hiding algorithm for Color image is more commonly used regarding the color image as the cover image to embed the secret information.Therefore,the research of reversible data hiding technology based on color image is more importa nt and closer to practical application.In this thesis,we focus on the key problems of the existing algorithms,such as the low embedding capacity,can't really achieve adaptive embedding and unable to resist geometric attacks.Specific contents of this thesis are as follows:1.Aiming at the existing problems of reversible data hiding algorithm for color image,such as the poor performance of anti-rotation attacks and the acerb contradictory between the amount of embedded data and the perceptual quality of image,a novel reversible data hiding(RDH)algorithm for color image based on two-dimensional discrete cosine transform(2D-DCT)was proposed in this thesis?.The correlation among three color components of RGB,2D-DCT and 2D-DCT inverse transformation were used to embed and extract the secret information.Experimental results show that the proposed algorithm has good r obustness,and it also has a better ability to resist geometric attacks,such as rotation,nose and shear attacks.Furthermore,the embedded capacity can be selected adaptively.At the same time,the original color image can also be restored without distortion,and the stego-image keeps the better perceptual quality when the embedding capacity is large enough.2.In order to solve the problems that the existing algorithms,especially interpolation expansion algorithms,which is hardly applicable to the color i mage and of low embedding capacity,cannot alleviate contradictory between the amount of embedding capacity and the perceptual quality of image,a novel high capacity reversible data hiding(RDH)algorithm for color image based on bicubic interpolation expansion was proposed in this thesis.The proposed algorithm makes full use of the correlation among RGB color components and the interpolation room redundancy to embed the secret data in the form of one dimensional sequence.The four low bits of each color component,the edge interpolation pixel and the reference pixel can be selected as the embedding position.The adjacent 16 pixel values are used to predict the value of the interpolated pixel.Experimental results show that the maximum embedding capacity of the proposed algorithm could reach to 6.732 bpp,and the image quality was very good when the hiding capacity was large.At the same time,the proposed algorithm eliminated the location map,could adaptively select the hiding capacity,and solved the problem that the interpolation expansion algorithm was not suitable for color image.