It has great significance for protecting the image copyright with color image digital watermarking technique, which needs the watermarking algorithm has high robustness, good imperceptibility and short running-time. A blind colour image watermarking algorithm combined spatial domain and singular value decomposition (SVD) is designed to protect the rightful ownership of color image in this paper. The theoretical principle combined SVD and spatial domain is first discussed and proposed in this paper. Based on the derived principle, the watermark information can be directly embedded into the maximum singular value (MSV) of the host image in the spatial domain by the new quantization index modulation with variable quantization step, and the embedded watermark information can be directly extracted from the MSV of the watermarked image block in the spatial domain with geometrical correction. The contributions of this paper include the following four points: (1) the relationship between the changed MSV of SVD and the average changed value of image pixel in the spatial domain is the first derived in this paper; (2) the presented method has the merits of both spatial-domain technique and transform-domain technique; (3) the relationships of each component of the color image are used to improve the invisibility and the geometrical correction of watermarked image is also adapted to further improve the robustness; and (4) this presented method overcomes the false-positive problem that existed in many watermarking methods based on SVD. Simulation results demonstrate the new presented color image watermarking technique has better imperceptibility, higher robustness and shorter running-time compared with some state-of-the-art methods.

中文翻译：

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一种结合空间域和SVD的盲彩色图像水印算法

彩色图像数字水印技术对图像版权保护具有重要意义，要求水印算法具有鲁棒性强、不可感知性好、运行时间短等特点。本文设计了一种结合空间域和奇异值分解(SVD)的盲彩色图像水印算法来保护彩色图像的合法所有权。本文首先讨论并提出了SVD与空间域相结合的理论原理。基于推导原理，通过可变量化步长的新量化指数调制，可以将水印信息直接嵌入到空间域中宿主图像的最大奇异值（MSV）中，嵌入水印信息可以直接从空间域水印图像块的MSV中提取，并进行几何校正。本文的贡献包括以下四点： (1) SVD的变化MSV与图像像素在空间域的平均变化值之间的关系是本文首次推导出来的；(2) 所提出的方法兼有空间域技术和变换域技术的优点；(3)利用彩色图像各分量的关系来提高不可见性，同时对水印图像进行几何校正，进一步提高鲁棒性；(4) 该方法克服了许多基于 SVD 的水印方法中存在的误报问题。