关键词: 数字水印, 哈达玛变换, 离散小波变换, 离散余弦变换, 奇异分解

Abstract: Because embedding only one kind of watermark in digital products can not satisfy people's demand anymore, in this paper, based on the orthogonality principle of Hadamard transform and the relative stability of Singular Value Decomposition (SVD) and so on, a digital watermarking algorithm for four color images using Hadamard transform and SVD in Discrete Wavelet Transform-Discrete Cosine Transform (DWT-DCT) domain was proposed. First, the four watermarking images were processed by Hadamard transform in order to become one watermark, and the one watermarking was transformed by SVD. The original image was transformed by DWT, DCT and SVD. Then the image was embedded by watermarking. Tests show that the algorithm not only can embed multi-watermarking at the same time to improve inbuilt information quantity, but also has a very strong robustness.

Key words: digital watermarking, Hadamard transform, Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT), Singular Value Decomposition (SVD)