Statistical Measures for Differentiation of Photocopy from Print technology Forensic Perspective

Forensic document examination plays an important role in providing the evidence to the court related to disputed documents. Emerging print technologies are posing challenges to document examiner in identification of source of document. Recent trends suggest the need for good preprocessors and post analysing tools which characterize printed text for identification of print technology. Each printing technology differs in their process of placing marking material on the target. Image analysis methods along with statistical tools are applied to study class characteristics of document for identifying the source of the document. This paper focuses on frequently used word like 'the' as test sample for characterizing printed text. The proposed algorithm is based on analysis of histogram of printed text image. Statistical measures skewness and kurtosis of histogram are used as features for distinguishing inkjet print from its photocopy.