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Detection of Pretreated Fingerprint Fluorescence Using an LED‐based Excitation System
Author(s) -
Takatsu Masahisa,
Shimoda Osamu,
Onishi Kyoko,
Onishi Akira,
Oguri Naoki
Publication year - 2008
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2008.00773.x
Subject(s) - fluorescence , fingerprint (computing) , light emitting diode , materials science , rhodamine 6g , halogen lamp , optics , optoelectronics , computer science , artificial intelligence , physics
Optimization of a light emitting diode (LED)‐based excitation system for the detection of pretreated fingerprint fluorescence is described. Fluorescent ridges can usually be excited by irradiation with forensic light sources such as xenon arc lamps or quartz‐halogen lamps with high‐power output and suitable filters. However, they are too expensive for many crime laboratories in smaller organizations. We concentrated on LEDs which have advantages over conventional light sources in that they are simpler and of lower cost, but the power output and quality of each individual LED unit is not sufficient for the detection of weak fluorescent ridges. To resolve this subject, blue and green LED arrays composed of ninety LED units were adopted and suitable low pass filters for them were designed. An experimental system, consisting of blue and green LED arrays with the suitable low pass filters for illumination, high pass filters for viewing, a digital camera and a computer, was tested. The fluorescent images of cyanoacrylate ester fumed/rhodamine 6G stained fingerprint on white polyethylene sheet and weak fluorescent ridges of ninhydrin/indium chloride treated fingerprint on white paper were successfully detected and photographed. It was shown that the improvement of LED beam in intensity and quality can compensate the disadvantages, resulting in well‐contrasted images.