A Multiresolution Robust Watermarking Approach for Scalable Wavelet Image Compression

摘要

This paper proposes a multiresolution blind watermarking approach in wavelet domain. The proposed approach performs a multiresolution decomposition of the logo (watermark) image. The logo insertion is started from the lowest frequency subband of the decomposed image and each decomposed logo subband is inserted into its counterpart subband of the decomposed image. The watermarked image does not show any perceptual degradation. To test the scalability features of the approach and robustness of the watermark against image compression, the watermarked image was first encoded by a highly scalable modification of SPIHT and then decoded at different bitrates and spatial resolutions. Multiple spatial resolution levels of the logo is progressively detectable from the decoded watermarked image. Experimental results confirm scalability features of the approach and its robustness against lossy compression. This approach could efficiently provide security for visual image transmission especially over het-erogenous networks, where different end-users need to be differently (in quality and resolution) served according to their device capability and network access bandwidth.