一种适用于QR码的彩色图像数字水印算法

针对彩色图像数字水印算法存在鲁棒性能差的缺陷，提出一种适用于QR码的彩色图像数字水印算法。将彩色载体图像从RGB空间转换到YCrCb空间，提取其Y分量并实施三级DWT、DCT和SVD操作获取对角矩阵；利用加性规则将实施Logistic映射和Arnold变换后的QR码嵌入对角矩阵中。实验结果表明:嵌入QR码的彩色图像PSNR值为59.4919，经过噪声、压缩、旋转、对比度变化等攻击后，其PSNR值和NC值分别稳定在30和0.98以上，提取的QR码都可通过手机扫描识别，解决了抗攻击能力差的缺陷。

Digital watermarking algorithm for color images on QR codes

Aiming at the poor robust performance of digital watermarking algorithms for color images, we propose a digital watermarking algorithm for color images applied to QR codes. A color carrier image is converted from RGB space to YCrCb space, in which the Y component is extracted and three-level discrete wavelet transform, discrete cosine transform, and singular value decomposition operations are gradually implemented to obtain the diagonal matrix; the QR code watermarking image implemented by a logistic chaotic map and an Arnold transform is successively embedded in the diagonal matrix through additive rules. The experimental results show that the peak signal-to-noise ratio (PSNR) value of the color image embedded with the QR code is 59.491 9. After the attacks of noises, compression, rotation, and contrast change, the PSNR and normalized correlation values are stably above 30 and 0.98, respectively. The extracted QR codes can be recognized by mobile phone scanning, which solves the poor anti-attack capability.