NCJ Number
150624
Journal
Journal of Forensic Sciences Volume: 39 Issue: 4 Dated: (July 1994) Pages: 920-932
Date Published
1994
Length
13 pages
Annotation
This discussion of Fourier transformation of a fingerprint image notes that its use along with subsequent filtering in the frequency domain has been found to be an effective way to improve images of fingermarks on interfering backgrounds.
Abstract
The masking/filtering of the frequency components corresponding to periodic background interference can greatly enhance the visibility of fingermark ridge detail, thus increasing the possibility of identification. The technique proves most successful when the operator has substantial control over mask creation and cutting. Specific examples demonstrate success in reducing periodic backgrounds that would otherwise have prevented fingermark identification. These images were captured directly as digital images or indirectly by digitizing conventional photographs. The same principles can be applied to shoemarks on periodic backgrounds. Full shoemarks require considerably higher sizes of images to obtain adequate resolution, but areas of shoemarks on periodic backgrounds can be specifically enhanced by capturing these areas at full resolution. Photographs, figure, and 12 references (Author abstract modified)