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Quantitative assessment of the discrimination potential of class and randomly acquired characteristics for crime scene quality shoeprints

NCJ Number
Date Published
148 pages

This research looked to validate the use of footwear impressions as a source of forensic evidence.


The objectives of this study were to: 1) simplify footwear impression data acquisition; 2) establish the baseline performance of an automated footwear classification algorithm; and 3) mathematically evaluate the frequency and similarity of randomly acquired characteristics (RACs) in high quality examples versus crime-scene-like impressions as a function of RAC shape, perimeter, and area. Results show that the unpredictable nature of crime scene print deposition causes RAC loss that varies from 33-100% with an average loss of 85%, and that up to 10% of the crime scene impressions fully lacked any identifiable RACs. Despite the loss of features present in the crime-scene-like impressions, there was a 0.74 probability that the actual shoe's high quality RAC map would rank higher in an ordered list than a known non-match map when queried with the crime-scene-like print. Moreover, this was true despite the fact that 64% of the crime-scene-like impressions exhibit 10 or fewer RACs.

Date Published: January 1, 2015