Forensic Image Analysis of Laser-Printed Documents

A preliminary study was undertaken to determine if objective measurements, using a proprietary image analysis system, may be routinely applied for the analysis of electrophotographic-printed documents, in particular laser-printed documents. Text and dot-quality objective measurements were studied to differentiate printed outputs. This paper highlights the complementarity of forensic image analysis to classical methods employed for the analysis of laser-printed documents. Some practical tests were prepared and discussed. Discriminant analysis correctly classified the samples from the tests, thus demonstrating that forensic imaging analysis is realistically applicable in closed-set cases (where the number of potential laser printers can be clearly defined) and in page substitution cases.