An imperceptible digital watermarking algorithm based on 4-level discrete wavelet transform, discrete cosine transform and singular value decomposition is designed. In this method, the 4-level diagonal sub-band image is obtained by performing the 4-level two-dimensional wavelet transform on the original image, and then a coefficient matrix is produced by applying the discrete cosine transform on the 4-level diagonal sub-band image. A diagonal matrix is constructed by performing the singular value decomposition on the coefficient matrix. The watermark is scrambled by Arnold transform and Logistic map, then the scrambled watermark is processed by the singular value decomposition. Later, the encryption process is completed by embedding the scrambled watermark singular value into the singular value of the coefficient matrix. Simulation results demonstrate that the proposed digital watermarking algorithm could resist JPEG compression attack, Salt and Pepper noise attack, Gaussian noise attack, filter attack, brightness change attack, geometric attack, cut attack, etc.

设计了一种基于四级离散小波变换，离散余弦变换和奇异值分解的数字水印算法。该方法通过对原始图像进行四级二维小波变换得到四级对角子带图像，然后对四级对角线进行离散余弦变换得到系数矩阵。子带图像。通过对系数矩阵执行奇异值分解来构造对角矩阵。通过Arnold变换和Logistic映射对水印进行加扰，然后通过奇异值分解处理加扰的水印。随后，通过将加扰的水印奇异值嵌入系数矩阵的奇异值来完成加密处理。