Abstract: The paper proposes an improved adaptive algorithm based on DCT according to the characteristics of texture，luminance of original image and the feature of human visual system.The algorithm makes pretreatment of watermarking image with Arnold transform，adaptively chooses scaling parameter of embedding and makes a binary watermarking image embedded into the original image，which implements the robustness and invisibility of algorithm.The experimental results show that this algorithm is robust and stable to common digital image processing operations.

Key words: Discrete Cosine Transformation（DCT）, Arnold transform, scaling parameter, adaptive watermarking

摘要： 基于原始图像的纹理特征和亮度特征以及人类视觉系统的特点，给出一种改进的基于DCT的自适应嵌入水印算法。算法采用Arnold变换对水印图像进行预处理，自适应选择强度因子，将一幅二值水印图像嵌入到原始图像中，实现了水印的不可见性和鲁棒性。仿真实验结果表明，算法对常见的图像处理操作具有较强的鲁棒性和稳健性。

关键词: 离散余弦变换, Arnold 变换, 强度因子, 自适应水印