NCJ Number
142978
Journal
Journal of Forensic Sciences Volume: 38 Issue: 3 Dated: (May 1993) Pages: 521-529
Date Published
1993
Length
9 pages
Annotation
A second-generation time-resolved luminescence imaging system has been developed that will better satisfy the practicality requirements for use by law enforcement agencies.
Abstract
The system design was matched to rare earth compounds with which fingerprints are treated using either ninhydrin/zinc chloride for smooth surfaces, or rhodamine-6G staining for porous surfaces. The imaging system uses a desktop computer and a digital CCD-camera incorporating a gateway microchannel-plate image intensifier; it provides flexibility of image acquisition and processing and hard-copy output and is user-friendly. Designers chose the argon-ion laser as the excitation source; the laser output is tightly focused onto the chopper blade in order to get a sharp cut-off. The chopped laser light is then examined by a liquid light guide which transmits both visible and near-UV light. The camera, mounted either on a zoom-stereo microscope or on a standard tripod, has computer-set controls consisting of gate width, delay, and maximum gain. The interface consists of a microprocessor gateway computer, two high-resolution monitors, and additional image processing hardware and software. In addition to fingerprint work, the time-resolved imaging system could be extended to DNA typing and labeling, immunoassays, and bioassays associated with rare earth labeling compounds. 11 figures and 13 references