Informed embedding for multi-bit watermarks

Informed embedding is the practice of tailoring each watermarking pattern according to the cover-Work in which it is to be embedded. The objective is to attain an optimal trade-off between estimates of perceptual fidelity and robustness. To date, our own studies of informed embedding have been limited to watermarks with very small data payloads. Our purpose in the present paper is to develop a method of informed embedding that is suitable for watermarks with large data payloads. The method we develop employs an estimate of robustness based on the amount of white noise that can be added before a message error becomes likely. We present an iterative, Monte-Carlo algorithm that tries to ensure watermarks are embedded with a specified value of this robustness estimate. This algorithm is tested in an image watermarking system, and is found to successfully embed robust, 129-bit watermarks in 368 x 240 images.