A Blind Digital Image Watermarking Method Based on the Dyadic Wavelet Transform and Chaos Models

We present a chaos-based watermarking method for digital images using the dyadic wavelet transform (DYWT) and some chaos models. The values of wavelet filters are expressed in interval representation in order to use fast interval arithmetic techniques in the embedding procedure. Our watermark is a ternary-valued logo that is embedded into the high-frequency components, and the Rossler system and the Lorentz system are employed as chaos models. To increase the degree of security, we use chaos maps to generate a key, and the watermark image is reprocessed with this key. We describe some experimental results demonstrating that our method gives watermarked images that have better quality and is robust against attacks such as addition of Gaussian white noise, addition of salt & pepper noise, marking, and clipping.