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Accession Number PB2013-103824
Title Physical Matching Verification.
Publication Date Dec 2012
Media Count 61p
Personal Author N/A
Abstract A prototype system used for physical matching in 2D. The system has two main functions: one is to assist forensic experts in performing physical matching in an objective manner, and the second to collect statistics and build confidence levels regarding the physical matches. The first function receives input images of broken or torn pieces photographed on distinctive background. The system then extracts the contour of each piece and lets the user choose a segment on one of the contours as a target for matching. The system then runs a search on the other contours, finds potential matches and orders these candidates according to the quality of their fit with the target. Using the statistics from the second function the user can estimate the potential error rates of each candidate matching pair. The second function takes as an input multiple images of broken or torn pieces and then generates many examples of physical matching that are classified into two populations: the correct matching pairs and the non-matching pairs. The system gathers the frequencies of the matching error for the two populations and presents the results as two histograms. The outputs of the system are several statistical measures describing the quality of matching as a function of the matching error value. The user can find the probabilities of a match being right or wrong for any specific value of matching error and thus is able to compare between matching pairs, and find out which is the best evidence, even among different sizes or materials.
Keywords Contours
Criminal investigations
Detection
Errors
Evidence
Forensic science
Images
Matching pairs
Photographs
Physical matches
Statistics
Verification


 
Source Agency Office of Justice Programs.
NTIS Subject Category 91C - Fire Services, Law Enforcement, & Criminal Justice
43D - Police, Fire, & Emergency Services
57F - Cytology, Genetics, & Molecular Biology
62F - Pattern Recognition & Image Processing
Corporate Author National Inst. of Justice, Washington, DC.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1309
Contract Number 2005-IJ-R-051

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