Wavelet-based readable watermarking algorithm using adaptive quantization

This work proposes a readable image-watermarking scheme based on adaptive quantization in wavelet domain. In order to increase the algorithms robustness and ensure the watermarks integrity, error-correction coding techniques are used to encode the embedded watermark .The watermarking bit is embedded in the LL band repeatedly through adaptive quantization. Before the watermark is embedded, the characteristics and tree structure relation of wavelet coefficients confirm a correlation mask for lowest coefficients, and then its corresponding mask controls the quantization step of every lowest coefficient. The experimental results show that the proposed algorithm is effective and robust to common image processing operations and some geometric operations, such as JPEG compression, JPEG2000 compression, filtering, adding Gaussian noise and row-column removal.