Abstract: This paper proposes a color image digital watermarking algorithm based on CDMA（Code Division Multiple Access） and HVS（Human Visual System）.To improve the security，CDMA is used to spread spectrum of the original watermarking.Fully considering the characteristic of HVS during embedding，this algorithm embeds the watermarking into the selected mid-band DCT coefficients of the original image.Based on series of attacking experiments，the results indicate that this method is efficiently invisible and robust against varies image processing operations.

Key words: digital watermarking, Code Division Multiple Access（CDMA）, Human Visual System（HVS）, Discrete Cosine Transform（DCT）, Walsh code

摘要： 提出一种基于CDMA（码分多址）和HVS（人类视觉系统）的彩色图像数字水印算法。该算法对原始水印进行CDMA扩频处理以提高安全性。水印嵌入过程中，充分考虑了HVS的特点，将原始图像进行分块后，将水印信息嵌入原始图像的纹理块的DCT中频系数中。实验表明该方法能够有效地抵抗多种图像处理操作，具有良好的不可见性和鲁棒性。

关键词: 数字水印, 码分多址, 人类视觉系统, 离散余弦变换, Walsh码