Printer forensics based on page document´s geometric distortion

A printed document can provide intrinsic features of the printer so as to distinguish which printer it comes from. But how to extract the intrinsic features is critical in printer forensics. In this paper, the page document´s geometric distortion is extracted as the intrinsic features, and a printer forensics method based on the distortion is proposed. Firstly projective transformation model is used to model the geometric distortion. After the feature point set of the model is extracted, the model´s parameters considered as the geometric distortion features can be estimated, and then the model´s error pattern can be obtained. During the process, the least squares method is used to estimate the model´s parameters, and SVM technique is used for classification. The effectiveness of the model´s parameters in the printer forensics is demonstrated by experimental results.