NCJ Number
218567
Journal
Journal of Forensic Identification Volume: 57 Issue: 3 Dated: May/June 2007 Pages: 414-434
Date Published
May 2007
Length
21 pages
Annotation
This article explores the usefulness of polynomial texture mapping (PTM) technology for forensic shoe and tire impression evidence.
Abstract
Results of the evaluation reveal that PTM technology can successfully be used in the forensic field and has the potential to produce better resolved images for the comparison of known shoe soles or tire treads to crime scene impressions. Specific results indicated that PTM images and enhancements improved the visibility of detail in some of the impressions under analysis when compared to traditional photography techniques, including improvement of the visualization of texture within a shoe or tire impression. PTM technology thus gives the examiner the best opportunity for visualizing unique characteristics in impression evidence. PTM technology also has the advantage of being cheaper to operate than traditional sidelight and casting techniques. The authors explain that PTM technology has been used in art galleries and for the display of ancient clay tablets and fossil remains because it enhances the detail. Working with a National Institute of Justice research grant, the authors undertook a 3-part project: (1) to construct a laboratory-based PTM dome, purchase and test camera equipment, and develop software to synchronize the digital camera control with the flash sequence; (2) to test the PTM technique with different types of impression evidence; and (3) to design and construct the portable field unit for use with the device. Each phase of the project is described followed by a discussion of the testing and results for each phase. The PTM process was tested using impressions from athletic footwear, work boots, dress shoes, casts of impressions found in mud and soil, and impressions made on cardboard. The PTM technique can be varied and future research should evaluate how the technique handles other types of comparative evidence such as latent prints and questioned documents. Contact information is presented. Figures, references