Abstract: In this paper，a new semi-fragile watermarking scheme for color image authentication is proposed，in which the watermark is embedded in the SVs（Singular Values） of the Dlocks within wavelet subbands by an adaptive quantized method.DWT is performed on the extracted and linearly modified luminance information matrix based on the features of YIQ.The two-dimensional transformed network generated by the low-dimensional Tent chaotic map is used to encrypt the embedded watermark.Only one initial value is required，which improves the simpleness of the scheme.The results of the experiment show that the proposed scheme is robust to JPEG compression but extremely sensitive to malicious manipulations.

Key words: watermark, authentication, SVD, DWT, Tent chaos

摘要： 提出了一种针对彩色图像认证的半脆弱水印方案，彩色图像亮度信息通过线性变化处理后进行离散小波变换（DWT），对低频子图分块后进行奇异值分解（SVD），将置乱后的二值水印信息通过自适应量化嵌入到奇异值中实现内容认证。线性变化处理能改善由水印带来的对彩色图像明暗度的影响，同时利用一维Tent混沌的特性构成混沌二维置换网络，只需要一个初值，使算法更加简单。由实验结果表明该算法对JPEG压缩稳健，而对恶意操作敏感，同时水印提取是盲提取的。

关键词: 水印, 认证, 奇异值分解, 小波变换, Tent混沌置乱