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Proceedings Paper

Computerized tool mark comparison
Author(s): Gavriel Feigin; Arie Aperman; Eliot Springer; Noam Jungmann
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Paper Abstract

The computerized toolmark comparison system is based on a cross correlation between a striation mark left by a tool on a lock and a test mark made by a suspect or the data base. The cross correlation is applied in the frequency domain for time saving. The area to be correlated is defined by the toolmark expert. A profile line is calculated and displayed based on the defined area. The two compared images may appear relatively shifted to one another, or only part of the toolmark that appears in the other. The same length of profiles is chosen from the two samples for entering to the updated correlation process. All possible correlations are checked by cutting and shifting through all cobinations. The database contains the defined images and the profiles calculated from them. The system consists of a 486 PC with a frame grabber and a video camera attached to a microscope. Results show that if the striation marks are clear and are wider than a minimum pixel limit, the correlation result higher than 0.6 is a possible match and has to be checked by the expert for a final decision. Future plans are to implement a 2D correlation. This method will enable us to deal with combinations of striations which are found frequently in real case work.

Paper Details

Date Published: 1 September 1995
PDF: 6 pages
Proc. SPIE 2567, Investigative and Trial Image Processing, (1 September 1995); doi: 10.1117/12.218470
Show Author Affiliations
Gavriel Feigin, Hebrew Univ. of Jerusalem (Israel)
Arie Aperman, Israel Police Headquarters (Israel)
Eliot Springer, Israel Police Headquarters (Israel)
Noam Jungmann, Israel Police Headquarters (Israel)

Published in SPIE Proceedings Vol. 2567:
Investigative and Trial Image Processing
Leonid I. Rudin; Simon K. Bramble, Editor(s)

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