NCJ Number
136544
Journal
Journal of the Forensic Science Society Volume: 32 Issue: 1 Dated: (January/March 1992) Pages: 15-25
Date Published
1992
Length
11 pages
Annotation
This paper outlines a method for extracting contours of the pressure exerted by feet on the ground, either directly or through the soles of shoes, and of the wear patterns on shoe soles.
Abstract
It has long been held that information about a person is contained in the shape and position of the general shoe-wear apparent on the shoe sole. Currently, this information is virtually ignored because of lack of a suitable, objective method for extracting it from a shoemark as well as lack of an analysis technique by which to compare the shoe-wear patterns extracted from different shoes or from one shoe at different times. This extraction problem has prompted the work reported in this paper. This paper describes a computer-based technique that allows the extraction of the general shoe-wear from shoemark images, contours of the wear patterns, and also isobars of the pressure distribution between foot and ground. This work is the first phase of a program that examines the individuality and distinguishability of wear patterns on shoe soles, pressure patterns, and the relationship of the two patterns. The analyses reported in this paper have been of shoeprints and of the pictures produced by a dynamic pedobarograph. The first procedure in the extraction of the information from images involves low-pass filtering in the Fourier domain, performed by a microcomputer and frame-grabbing system. The boundaries of the regions in the resultant images are then extracted from the filtered images to display the shape of constant pressure areas and of the general shoe wear. 4 figures and 25 references