Research Of Secret Image Sharing Method Based On Discrete Wavelet Transform

With the rapid development of modern communication technology and the wide application of computer internet technology, information sharing and transmission becomes more and more important. It has brought us great convenience and a great number of information security problems as well. Such as information theft, copyright protection of multimedia data and image authentication. But traditional security protection way-cryptography can't indeed solve the above problems. Steganography hides the secret information into public carrier to transmit it secretly, which can not arouse attacker's attention and reduce the possibility of being intercepted and captured.There is some fault in recent Steganography, in which gray-image is used as carrier, which restricts the application domain. Further more, one secret image is hidden in one carrier image, the receiver couldn't obtain anything once the stego-image is attacked or destroyed.This paper brings forward a new secret image sharing method based on discrete wavelet transform according to the fault of recent methods. This method is reparation of traditional image sharing technique, which controls the vision quality of the extracted secret image by defining several thresholds. The thresholds are defined as ( r1 ,r2,...,rk ,n). Sharing the secret image into n shadows, when the number of shadows are more than rk , the receiver can obtain all the information of the secret image, when fewer than r1 , we can get nothing, when the number between the two values, the more shadows, the better quality of the secret image.Adapting Arnold transform based on block not only ensure the relativity between pixels, but also improve the invisibility and the security of the secret information. discrete wavelet transform and Bit-plane scanning is used to ensure the more information the frontier pixels of each block pixels. A well visual effect can be achieved adapting Least Significant Bit substitution method to imbed each shadow image into R, G and B channels of the cover image. The experimental results show that our method can achieve the better invisibility, higher security and the big imbedding space.