Arnold变换是数字图像置乱中常用的一种方法。但是,Arnold置乱具有周期性,并且其周期有一定的规律。因此可以采用穷举法计算出置乱时使用的加密密钥,轻而易举地还原出水印信息,安全性不高。为此,应用一种改进的水印预处理技术,将混沌序列和图像置乱技术结合起来对灰度水印图像进行加密。实验结果证明了算法的可行性。
Arnold transformation is a method usually used in image scrambling.But,Arnold is cyclical scrambling,and its cycle has certain rules.So can use exhaustively scrambling method to calculate the encryption keys used,easily the watermark and safety reduction is not high.Therefore,an improved watermark preprocessing technologies is applied,the chaos theory and image scrambling technology combine encrypt of watermark image.The experiment results prove the feasibility of this algorithm.