NCJ Number
182494
Journal
Journal of Forensic Identification Volume: 50 Issue: 3 Dated: May/June 2000 Pages: 271-275
Date Published
May 2000
Length
5 pages
Annotation
A novel technique based on a three-dimensional (3D) laser recording of surface topography is useful for dealing with fingerprints on cartridges and expended cartridges.
Abstract
Conventional photography produces unsatisfactory results due to the strong curvature of the cartridge surface. Local damage to the cartridge case due to mechanical contact with the ejection port or to post-ejection squeezing accidents may emphasize this problem. In addition, dedicated photographic techniques or combining a number of photographs are not in widespread use and may not be applicable to damaged, imperfectly cylindrically shaped objects. The authors’ technique rested on a 3D recording of the surface topography. A UBM-profilometer recorded the data. The system uses a sensor head that could be positioned along a translational axis while a rotational stage rotates the sample. These features make the system ideally suited for the study of the surfaces of cylindrical objects. Computer software transforms the reflectivity values into 8-bit gray values and writes them to a file using the well-defined Tagged Image File Format (TIFF) available on most computing platforms. Figure and 8 references