An image watermarking scheme based on multiresolution analysis

A robust blind image-watermarking algorithm is proposed. The proposed algorithm is based on both the Discrete Wavelet Transform (DWT) and the Wavelet Packet Transform (WPT). The main idea of the proposed algorithm is to decompose the host image using DWT and WPT according to the size of the watermark. The watermark is embedded in the fine-scale bands of the WPT of the fine-scale bands of the last DWT decomposition level of the host image. Each pixel in the watermark is split into three parts, and the One-Bit per Coefficient (OBC) approach is applied for embedding the pixel. The final step is to compute the inverses - IWPT and IDWT - to obtain the watermarked image. In this algorithm, the obtained watermarked image has high Peak Signal to Noise Ratio (PSNR) and the extracted watermark has very high Normalized Correlation (NC). The proposed algorithm is robust to a variety of signal operations.