目的 提出一种具有高度抗攻击能力的数字水印算法。方法 将载体图像从RGB色空间转换到YCbCr色空间， 以其Y通道作为嵌水印通道； 将文字信息编码为QR码作为数字水印， 再对其Y通道进行离散余弦变换； 最后在其中频区域嵌入数字水印。结果 该算法重建的水印图像与原水印相似度极高， NC值达到0.99。同时， 水印的嵌入对图像质量影响很小， PSNR值高达42.3115， 且能抵抗多种噪声的攻击。结论 该数字水印技术兼具了水印的安全性与鲁棒性， 能够基本满足各类数字作品版权保护的需要。

A new digital watermarking algorithm which can enhance the attack resistance ability of the color image was proposed. The watermarked host image in RGB mode was converted to the YCrCb color space， and luminance Y component was used as the embedded watermark channel. Literal information was encoded with QR code as the digital watermark, and then embedded into the intermediate frequency area in Y channel, which was previously subjected to DCT transformation. The experimental results showed that the similarity between the reconstructed watermark and the original watermark was very high, and the NC value reached 0.99. Meanwhile, the embedding of watermark had little effect on the image quality, with a PSNR value of 42.3115, and it could resist attack of various noises. The digital watermarking technology did not only keep the security and robustness characteristics of watermark, but could also meet the needs of copyright protection in all kinds of digital works.