Adaptive Image Watermarking Optimized for Pre-Specified Fidelity

Embedding watermarks into images can be referred to as a constrained optimization problem. Keeping image quality acceptable and maximizing watermark strength is more meaningful and applicable to a user than fixing strength parameter and minimizing distortion. In this paper, we propose an approach that hides watermarks in relationships between wavelet coefficients. This approach would maximize the strength of the watermark while keeping the perceptual distortion of watermarked images, measured with PSNR equal to an acceptable value specified by the user. Experimental results show that the watermark is still detectable after common image processing operations such as JPEG compression, Gaussian filtering and sharpening.