Large-capacity Image Hiding Algorithm Based On The Wavelet Domain

As an important research technology in multimedia information security field, image hiding technology takes advantage of the redundancy of carrier image and the feature of human visual system, then embeds the secret information into the carrier image. How to realize large capacity information hiding is the essential trend of research due to the importance of information protection in the future.According to the difference of embedding domain, image hiding methods can be divided into spatial domain hiding and transform domain hiding. Typically, hiding algorithm in spatial domain is simpler, faster than hiding algorithm in transform domain. It helps to real-time process, but it has a weaker robustness. Wavelet transform is widely used among hiding methods in transform domain because it has a good time-frequency and multi-resolution character. We can get better robustness through hiding secret information into wavelet domain.In this paper, information hiding in wavelet domain is combined with information divided-storage to realize large capacity information hiding. We decompose each pixel of secret image and then embed decomposed information into wavelet domain of carrier image. The experimental results show that this algorithm has larger capacity than LSB hiding algorithm. Furthermore, isolated storage of secret image makes higher security.Storing 3D object is a difficult target because 3D object has more data than image. In this paper, eigenimages of 3D object are obtained by using principal component analysis method. Wavelet coefficients of eigenimages are embedded into the wavelet domain of the carrying image. Based on the relationship of extracted eigenimages and coefficients, a series of images are reconstructed. The proposed method does not store the object images directly, but store the eigenimages which contain information of the 3D object. The experimental results show that the features of 3D object are effectively embedded into the carrying image, and the proposed algorithm has a high capacity.In this paper, another algorithm to realize large capacity hiding is utilizing the character of digital hologram, which can store large quantity of information. First, we simulate several fresnel diffraction holograms via different wavelength of laser source and different intersection angles between object beam and reference beam. Then, we fuse these holograms together and embed the mixed hologram into the wavelet domain of carrier image. The experimental results show that the spectrum of extracted mixed hologram can be separated successfully. We can revert original secret images through computer simulation.