关键词: 离散余弦变换, YIQ色彩空间, Amold变换, 彩色载体图像, 数字水印

Abstract: As a main method for copyright protection, the techniques of digital watermarking have been widely researched and used. However the practical techniques in color image digital watermarking is lesser studied, especially for the embedding algorithm of grayscale watermarking signal. Considering the characteristic of Human Visual System (HVS), proposed method in this paper adopts YIQ color space, and embeds a grayscale image into the luminance Y of the color image by using discrete cosine transform, and increases the bit embedding quantity in more complex blocks. In addition, through Amold transform, the watermarking image is hashed to eliminate the spatial correlation among pixels, which enhances the algorithm’s anti-attack ability. The experimental results show that the proposed watermarking scheme is robust for various attacks such as noise adding, JPEG compression, cropping, and image enhancement.

Key words: discrete cosine transform (DCT), YIQ color space, Amold transform, color host image, digital watermarking