凭借着高性能的计算机、高分辨率的数码照相机以及成熟的照片编辑软件,用户可以轻松地按照自己的意愿来修改数字图像.由于成功的伪造不会在图像上留下篡改的视觉痕迹,也就不会被人眼所感知,但是也会不可避免地留下一些修改过的电子痕迹.大多数的伪造会在篡改图像之后采用边缘和区域平滑的方法来使图像显得完整、统一.描述了图像在修改前后的区别,之后将引入"不和谐点"的概念,然后提出了一种在图像的任意地方自动检测平滑区域的方法,以表明可能存在的篡改.该技术方法不需要嵌入任何信息.

With powerful computer, high-resolution digital cameras, and sophisticated photo editing software, users can easily manipulate and alter digital images as they wish. Although good forgeries may not be perceptible by human eyes because no visual clues of tampering are left, they may leave some traces of digital tampering that can not be avoided in the media during tampering process. Most digital forgeries employ edge and region smoothing after the contents are manipulated or altered. This paper describes how smoothing introduces disharmony between authentic regions and tampering regions, and then presents a method to automatically detect smoothing regions at any part of an image that indicate possible tampering. The technique works well without any embedded information such as digital watermark.

Supported by the National Basic Research Program of China under Grant No.2006CB303104 (国家重点基础研究发展计划(973)