一种彩色图像可恢复半脆弱数字水印算法

提出了一种彩色图像可恢复半脆弱数字水印算法,该算法可准确地实现篡改图像的检测、定位及恢复。算法先将彩色图像从RGB空间转换到YCbCr空间,从各分量提取恢复信号,嵌入色度分量Cb、Cr的小波域中高频子带,然后将Y分量的L+1级小波系数调制成检测水印,嵌入到Y分量的最低频子带。认证时,从Y分量中提取检测水印,初步判断篡改位置,再从Cb、Cr分量中提取恢复信号,恢复篡改区域。仿真实验表明,该算法不仅能对彩色图像进行认证及恢复,并对常规信号处理操作具有较好的脆弱性。

An auto-restorable semi-fragile watermarking algorithm for color image

A semi-fragile digital watermarking algorithm for color image tamper detection and recovery is proposed. Firstly, the color image is converted from RGB space to YCbCr space. Secondly, recovery signals are extracted and embedded into the middle and high-frequency wavelet coefficients of the chrominance components (Cb and Cr), then the L+1 level wavelet coefficients of the Y component are modulated into detection watermarking, which will be embedded into the low frequency coefficient of the Y component. When we authenticate, authentication watermarking is extracted from the Y component, the tampered positions are identified, and then recovery singles are extracted from the Cb and Cr components to restore the tampered areas. Simulation results show that our algorithm can  not only be used in color image authentication and recovery but is also fragile to regular manipulation.