AVOIDING HARD DECISIONS IN ADAPTIVE WATERMARKING

ABSTRACT In this paper, we describe the coupling of content adaptive watermark decoding and soft-decision forward error correction. We deduce three fundamental properties from adaptive watermarking methods switching between different embedding strengths. It is shown how a weighting process at the decoder can be used to build up an overall soft processing watermarking. No pre-distortion has to be used, and hence, the image quality is not degraded. In this conjunction, even adaptation techniques can be used where it is computational infeasible to project a pre-distortion back onto the host image. Experimental results indicate the improvement in bit error correction during watermark retrieval by a factor of 5. Without loss of security, performance or functionality our new technique can be integrated very easily into numerous watermarking applications

A Secure Semi-fragile Watermarking Algorithm for Image Authentication in the Wavelet Domain of JPEG2000

In this paper, we present a new authentication method in the wavelet domain of JPEG2000, which is robust to re-compression, resolution changes and noise. We show that, because of its bit plane oriented processing, JPEG2000 is more suitable for the integration of an authentication watermarking algorithm than JPEG. The disadvantages of JPEG-based authentication schemes are discussed. It is shown that our authentication scheme is secure in contrast to most of the authentication schemes proposed so far in the wavelet domain. The security of our authentication algorithm depends only upon hash algorithm and encryption. Since these algorithms can be updated easily in our authentication scheme, the proposed authentication algorithm will also be secure in the future