中文摘要：

针对移动终端多媒体信息版权保护的问题,提出了一种改进的基于DCT的半脆弱盲数字水印算法,并将其与当前流行的智能手机平台Windows Mobile相结合,开发一款应用于智能手机的图像认证系统。在水印嵌入过程中,充分考虑人类视觉系统的特征,采用YUV颜色空间,把载体亮度分量Y进行DCT变换,将二值水印信息嵌入DCT中频系数中,中频系数的选定通过将系数量化与块的复杂度结合,依据＂特征丰富块多嵌入＂的原则实现。此外,为了增强水印的安全性对水印图像进行Arnold置乱,水印的提取不需要原始载体图像。实验证明,该算法不仅得到了较高的图像质量,而且具有很好的抗JPEG压缩性能。

英文摘要：

Focuses on copyright protection for multimedia information on mobile terminals,proposed an improved semi-fragile blind digital watermarking algorithm based on DCT,it combined with the current popular smartphone platform Windows Mobile,developed an image authentication system used in smartphone.In the watermark embedding process,considering the characteristic of human visual system,the method adopts YUV color space and the luminance Y of the color image by using discrete cosine transform,and then the binary watermark is embedded in middle frequency in DCT coefficients,selection middle frequency coefficient by coefficient quantization and complexity of block,and according to ＂increases the bit embedding quantity in feature-rich blocks＂ principle to achieve.In addition,through Arnold transform for watermark image in order to enhance the security of the watermark,extraction of the watermark need not origin host image.Experimental results show that the proposed algorithm not only improves image quality evidently,but also is robust to JPEG.