This paper presents a new passive image authenticate algorithm to check and measure the forged pictures and images in the regional copies and sticks. After reducing the image dimension by DWT (Discrete Wavelet Transform), the Tchebichef moment invariants is applied to the fixed sized overlapping blocks of a low-frequency image in the wavelet sub-band, and the eigenvectors are lexicographically sorted. Then, similar eigenvectors are matched by a certain threshold. Finally, the forgery part is identified by the threshold analysis. The experimental results show that proposed method can not only localize the copy forgery regions accurately, but also undergone some attacks like random noise contamination, lossy JPEG(Joint Photographic Experts Group) compression, rotation transformation etc. and reduce the amount of computation and improve the detection efficiency.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.