关键词: 图像取证, 小波变换, 灰度分布特征, 复制伪造区域

Abstract: Copy-move is a common forgery in the research field of digital image forensics，this paper proposes a detection approach based on wavelet transform and gray distribution feature of image blocks.DWT is applied to the image，and gray distribution feature is extracted on fixed-size blocks of low-frequency component in wavelet sub-band to yield a reduced dimension representation.In order to further reduce the computation，iterative division method combined with the use of similarity are used to search similar image block.Copy forgery regions are localized by detecting for all neighborhood vectors.The experiments demonstrate that the proposed approach can not only localize the copy forgery regions accurately，but also reduce the amount of computation and improve the detection efficiency.

Key words: image forensics, wavelet transform, gray distribution feature, copy forgery region