彩色数字图像的脆弱数字水印

针对彩色数字图像局部区域内容保护和认证,研究了彩色数字图像的脆弱数字水印.为了保证水印的安全性,利用三维二值混沌序列对原始二值水印图像进行加密,对提取的加密二值水印图像进行解密.嵌入载体图像的水印和从嵌入水印的图像中提取的水印均是加密水印.将彩色数字图像中被保护区域的三个分量的小波变换域分别嵌入加密水印,以保护其内容的完整性和不可篡改性.采用模运算实现水印的嵌入和盲提取.理论分析和实验结果表明,该脆弱水印算法对彩色数字图像保护区域内的任何篡改,都能够正确地检测和定位.

Digital Fragile Watermark of Color Digital Image

In light of the content protection and authentication of local areas in color digital images,a fragile watermarking algorithm of color digital image is studied.To ensure the security of digital watermark,using a three dimensional binary chaotic sequence,the original binary watermark image is encrypted,and the encrypted binary watermark images extracted from the watermarked image is decrypted.The watermarks embedded into the cover image and the ones extracted from the watermarked image are all encrypted watermarks.The encrypted watermarks are respectively embedded into the wavelet transform domains of the three components of the protected area in color digital image to protect the integrality and non tampering of its content.The embedding and blind extracting of digital watermarks are implemented by using modular arithmetic.The results of theoretic analyses and experiments have shown that the digital fragile watermarking can detect and locate any tampering of the protected areas in color digital images.