基于DCT系数哈希的图像篡改检测算法

随着数字图像处理技术的不断提高,大量的篡改图像充斥互联网和各类媒体,严重影响了人们的日常生活。因此,对图像的真实性和完整性进行判断的数字图像取证技术显得尤其重要。针对数字图像版权中常见的剪切组合篡改问题,文中提出了一种基于DCT系数哈希的图像篡改检测算法。在JPEG压缩过程中,首先提取Y通道的DCT系数矩阵,然后对所提系数矩阵进行DCT以构造出图像哈希,最后将图像哈希嵌入压缩码流的文件头。在篡改检测时,通过篡改图像对应的压缩码流构造出篡改图像哈希,将其与嵌入的源图像哈希进行比较以进行初次检测。为了达到像素级检测的目的,文中在初次检测结果的基础上提出了一种二次检测的算法。实验结果表明,所提算法不仅鲁棒性较好,而且构造的图像哈希长度较短,检测的准确率也提高了10%。

Image Forgery Detection Based on DCT Coefficients Hashing

With the continuous improvement of digital image processing technology,tampered images are flooded with the Internet and various media,seriously affecting people’s daily life.Therefore,digital image forensics technology,which can judge the authenticity and integrity of images,is particularly important.An image forgery detection algorithm based on DCT coefficients hashing was proposed,for dealing with the splicing forgery detection of digital images.In the process of JPEG compression,first,the DCT coefficient matrix of the Y channel after DCT is extracted,then the image hashing is constructed by DCT coefficients,and finally the image hashing is embedded in the header of file of the compressed code stream.At the time of tampering detection,a tampering image hashing is constructed by compressed code stream corresponding to the tampering image,and then compared with the embedded original image hashing for initial detection.In order to achieve the pixel-level detection,a method of secondary detection was proposed based on the preliminary detection results.The experimental results show that the proposed algorithm not only has good robustness,but also has a shorter hash length and a 10%higher detection accuracy.