Curvelet Transform Domain Information Hidden Method

The information hiding is a pioneer research area of information science. It has been widely studied and mainly applied in secret communication and protection of property rights. Information hiding has two major branches, steganography and watermarking. Steganography is used to hide secret messeage into cover media, the invisibility, capacity and undetectablity are important, while watermarking the latter one, is to embed the watermark into digital products for authentication. The focus of watermarking is on robustness and security.As a new multi-scale geometric analysis, the second generation curvelet transform (FDCvT) features multi-direction subbands and anistorpy property, which exceeds wavelet transform in representation of 2-D images. Literature has seldom been found in information hiding of second generation curvelet transform. We focus our research on it and the works accomplished are as following:(1) An digital image steganogarphy scheme was proposed. We chose a part of FDCvT coefficients to embed the secret based on the ridge component concept we defined and its orthogonal property was applied to enlarge the capacity. We used the error control coding to reduce the error rate and a blind extraction was also achieved. The experiments showed that our algorithm has better image quality and larger embedding capacity against the Jsteg method in DCT domain and QIM method in wavelet domain.(2) A semi-fragile watermarking method for image authentication using human visual system was proposed. We embedded the watermark into the coarse scale of second generation Curvelet transform adaptively, according to the texture and luminance factors of Curvelet HVS characteristics. Another masking of angular factor is introduced for higher security and the algorithm also uses blind extraction. Experimental results demonstrated the proposed method is robust against JPEG compression and common signal processing, and distinguishing them from malicious tampering, while good image visual quality is kept at the same time.(3) A distributed online multichannel monitoring system of high-voltage capacitive devices in transformer substations was implemented. The system has been installed and running steadily. A measurements of a much higher precision was achieved.