基于二维直方图移位的图像认证算法

针对如何检测数字图像内容是否完整、有无篡改,提高认证图像质量的问题,提出了一种基于二维直方图移位的图像认证算法。首先,在棋盘格结构中利用两种预测差值计算方法构建原始图像的二维直方图,由预先设定的参数选择可嵌入信道,并确定可嵌入信道峰值点的位置,将可嵌入信道移位。然后结合直方图信息嵌入方法将认证信息嵌入到图像分块中。在篡改检测过程中采用分层篡改检测方法,有效提高篡改检测准确度。实验结果显示,该算法不仅可以抵抗噪声攻击,而且当参数设定为2和4时,认证图像的平均峰值信噪比(PSNR)分别为52.37 dB和50.33 dB,进一步提高了图像质量。实结果表明,所提算法安全性高,可实现可逆水印,并准确定位出篡改区域。

Image authentication agorithm based on two-dimensional histogram shifting

In allusion to the problem that how to detect whether the digital image data is complete, and whether the image is tampered, an image authentication algorithm based on two-dimensional histogram shifting was proposed to improve the quality of the authentication image. Firstly, the two-dimensional histogram of the cover image was structured through two prediction difference value calculating methods. The embeddable channels were chosen by the preset parameters and the embeddable channel peak positions were determined and the embeddable channels were shifted. Then, the anthentication information was embedded into image blocks with histogram shifting method. Hierarchical tampering detection was adopted during the process of tamper detection to effectively improve the accuracy. The experimental results showed that the algorithm could resist noise attack, and the average Peak Signal-to-Noise Ratio (PSNR) of the authentication image was 52.37dB and 50.33dB respectively when the parameter was set as 2 and 4, which improves the quality of images. The resutls prove that the algorithm has high security, and it is able to implement reversible watermarking as well as precisely locationing the tampering region.