This paper presents an improved data hiding technique based on BCH (n,k,t) coding. The proposed embedder hides data into a block of input data by modifying some coefficients in the block in order to null the syndrome. The proposed embedder can hide data with less computational time and less storage capacity compared to the existing methods. The complexity of the proposed method is linear while that of other methods are exponential for any block sizen. Thus, it is easy to extend this method to a largen. The BCH syndrome coding for steganography is now viable ascribed to the reduced complexity and its simplicity of the proposed embedder.

A new informed image watermarking algorithm is presented in this paper, which can achieve the information rate of 1/64 bits/pixel with high robustness. Firstly, a LOT (local optimal test) detector based on HMM in wavelet domain is developed to tackle the issue that the exact strength for informed embedding is unknown to the receiver. Then based on the LOT detector, the dirty-paper code for informed coding is constructed and the metric for the robustness is defined accordingly. Unlike the previous approaches of informed watermarking which take the informed coding and embedding process separately, the proposed algorithm implements a joint coding and embedding optimization for high capacity and robust watermarking. The genetic algorithm (GA) is employed to optimize the robustness and distortion constraints simultaneously. Experimental results show that the proposed algorithm achieves significant improvements in performance against JPEG, gain attack, low-pass filtering and etc.

A DWT-HMM (hidden Markov model in wavelet domain) image watermarking algorithm with content-adaptive approach is proposed in this paper to optimized the trade-off between robustness and visual quality, which is characterized as follows: the entropy mask proposed by Watson is constructed in wavelet domain; the entropy mask and the new developed integrated HVS are used as the measures to adaptively select image components for watermarking; repeat-accumulation (RA) code with erasure and error correction is employed to synchronize the watermarked image; and a posterior HMM is utilized in watermark detection. Considerable improvement in robustness performance with the proposed adaptive algorithm is obtained over the previous DWT-HMM watermarking algorithm with stochastic embedding.