Readable watermarking algorithm based on wavelet tree quantization

The paper proposes a blind and readable image watermarking scheme based on wavelet tree quantization. In order to increase the algorithm´s robustness and ensure the watermark integrity, error correction coding techniques are used to encode the embedded watermark. In the watermark embedding process, the wavelet coefficients of the host image are grouped into wavelet trees and each watermark bit is embedded using two trees The trees are so quantized that they exhibit a large enough statistical difference, which is later used for watermark extraction. Experimental results show that the proposed algorithm is effective and robust to common image processing operations and to some geometric operations, such as JPEG compression, JPEG2000 compression, filtering, adding Gaussian noise and row-column removal, so a conclusion can be made that the proposed technique is practical.