A Robust Blind Image Watermarking Scheme in the SPIHT-Compressed Bit-Stream

Practical digital multimedia is usually encountered in compressed format, and as such it is highly desirable to develop watermarking algorithms that operate totally in the compressed domain. In addition, watermarking schemes working jointly with SNR-scalable compression algorithms would be of great interest since the watermarks could be entirely retrieved at a given bit-rate. In this context, this paper proposes a robust blind image watermarking scheme operating in the SPIHT-compressed bit-stream. First, the watermark, which is a binary sequence, is encoded with an error-correction coding and interleaved to minimize the error decoding probability and combat bursts of errors. Then, in the course of SPIHT encoding process, the list of significant pixels (LSP) is used to embed the watermark sequence in a uniform quantisation manner at a given threshold where the coefficients of interest are differently refined in the next passes. Experimental results, carried out on various images, have shown the robustness of the watermark in the presence of different attacks.