Forensic examination of laser printers and photocopiers using digital image analysis to assess print characteristics

The work in this paper describes a method that can assist the process of print identification with respect to the printing machine that produced it. The method used high spatial resolution and low-noise digital image analysis to measure the sharpness, intensity and size characteristics of individual text characters. The relative variations of these variables were used to identify the machine that produced the print under examination. The results showed that three machines could be distinguished and one of these machines also showed differences in the print produced when the toner cartridge was changed. (c) 2007 Society for Imaging Science and Technology.