Digital images have an inherent amount of noise typically uniform across the entire image is introduced by imags processing. So if images with different noise levels are spliced together would leave an evidence of tampering. Base on this characteristic

this paper presents a passive image forgery detection algorithm which uses blind estimation of background noise. By computing high order statistic characteristics of the background noise and estimating the neighboring overlap blocks

the algorithm could locate the forgery parts. Experiment results show its effectiveness in detecting forgery part in spliced images.