Using Julian set patterns for higher robustness in correlation based watermarking methods

Some of the most important classes of watermark detection methods in image watermarking are correlation-based algorithms. In these methods usually a pseudorandom pattern is embedded in host image. Receiver can regenerate this pattern by having a key that is the seed of a random number generator. After that if the correlation between this pattern and the image that is assumed to have the watermark is higher than a predefined threshold, this means that the watermark exists and vise versa. In this paper we showed the advantage of using the Julian set patterns as a watermark, instead of commonly used pseudorandom noisy pattern. Julian set patterns can be regenerate in receiver with few parameters such as coefficients of its function and an initial point, which can be embedded in the key. Our experiments showed that these patterns not only manipulate fewer numbers of pixels but also increase the robustness of watermark against attacks