NCJ Number
138346
Journal
Journal of Forensic Sciences Volume: 37 Issue: 4 Dated: (July 1992) Pages: 1076-1083
Date Published
1992
Length
8 pages
Annotation
A gateable, image-intensified laser system that permits the detection of latent fingerprints under high background light is described.
Abstract
The system is intended for crime scene work and for daylight conditions. In the case of visual inspection for laser development in a room light environment, the background will decrease image contrast; in extreme conditions, the background will submerge the fluorescence pattern altogether. Thus, the main problem is how to improve the fluorescent signal to background noise in daylight environments. In general, the intensity of laser-induced fluorescence is proportional to excitation power or power density. In the reported gateable, image-intensified laser system, the signal first passes through the lens onto the detector window. The electronics unit consists of two parts, the fundamental power supply for the intensifier tube and a synchronized, high-speed photoelectronic gate. Due to the system's time resolving and wavelength selecting, background suppression of 6 to 8 orders of magnitude can be achieved. 8 references, 2 tables, and 6 figures