Problems of Forensic Sciences 2009 Vol. 79 (LXXIX) 338-347
TRANSPOSITION FORGERY THROUGH IMAGE PROCESSING. A FRESH APPROACH TOWARDS ITS EXAMINATION AND DETECTION
Mahesh Chandra JOSHI1, Rajat CHOUDHARY1, Om Prakash JASUJA2
1Directorate of Forensic Science, Ministry of Home Affairs, Chandigarh, India
2Department of Forensic Science, Punjabi University, Patiala, India
Streszczenie
The arrival of plain paper copiers and digital image processing have added new dimensions to the nature and modus operandi of white-collar crimes based on the “cut-paste” techniques, transposition, etc. This study presents an actual case submitted to the laboratory for scientific examination and opinion wherein computer based digital image acquisition technology coupled with photocopying has been used as a tool both for the fabrication of documents and its scientific detection. The perpetrator of the crime used digital image acquisition and manipulative processing of signatures existing on some (other) genuine documents and their subsequent transposition for createing spurious documents. This was an attempt on the part of the perpetrator to mislead the examiners and law enforcementing agencies and also defy the axiom of forensic documents science that two exactly alike signatures in terms of their relative size and dimensions as well as perfectly superimposing with each other are non-existent due to the inherent and integral concept of dynamism and natural variability in the genuine signatures. Interestingly, various documents containing certified genuine standard signatures were also supplied for comparison with the questioned signatures, out of which two documents contained consisted source signatures. Various experiments were conducted and a fresh digital based methodology was devised to find out the exact percentage of reduction in the relative size and dimension of the questioned signature and finally, it was shown proved that the documents were are of spurious nature.
Słowa kluczowe
Examination; Forgery; Image acquisition; Transposition; Superimposition.