FORENSICS
DETECTING CRIME ONE SHOE AT A TIME
West Yorkshire Police teams up with Staffordshire University researchers to deploy 3D technology which has increased the probability of detecting an offence from 8.9 per cent without useful CCTV to 55.7 per cent with it
West Yorkshire Police has partnered with researchers from Staffordshire University to advance 3D scanning technology and develop a novel system to scan and identify the footwear worn by suspects. Selina Reidy, an identification expert from West Yorkshire Police, said: “With the increasing quantity and improving quality of surveillance footage, we are receiving a growing number of requests to identify the make and model of footwear caught on camera. Having access to a searchable database of interactive 3D models of footwear under both white and near infrared light will greatly improve the accuracy and efficiency of the current process. This work will expand and improve the current evidence base and, with continued development, will provide an additional forensic capability that informs police investigations.” The new scanning technique builds on the pre-existing and well-established practice of analysis of footwear impressions left at crime scenes and moves the idea on from just identifying footprints to working to identify a shoe by scanning the ‘upper’, critical as this is often the only identifiable item on CCTV. Claire Gwinnett, professor of forensic and environmental science at Staffordshire University, said: “The number of cases in which footage from body worn cameras, CCTV and even phones is used to catch perpetrators has increased. However, criminals often conceal their face and wear dark clothing which means there are few identifying features apart from their shoes, so the question is, how useful is this as evidence should the shoe be clearly identified by the scanning technology?”
40 | POLICE | FEBRUARY | 2024
Studies cited in The Value of CCTV
Surveillance Cameras as an Investigative Tool: An Empirical Analysis by Matthew P.J. Ashby, highlight that having useful CCTV evidence is associated with a significantly increased detection rate for all types of crime except drugs, fraud and public order. The largest change is for robbery, where
a powerful investigative tool for many types of crime. By adding further means of positively identifying individuals on CCTV, it is hoped the value of CCTV as an investigative tool can be increased. The research has been funded by the
“We record a video of a shoe on the turntable under each lighting condition, extract the frames and put it into software that stitches it all together to make a 3D model.”
the probability of detecting an offence increases from 8.9 per cent without useful CCTV to 55.7 per cent with it. The same paper notes that CCTV was judged to be useful in 65 per cent of cases in which it was available to British Transport Police between 2011 and 2015, underscoring the value CCTV has as
Police Star Fund and the end product is a fast, efficient, and importantly, affordable method for identifying footwear uppers by creating an interactive 3D image of a shoe under both normal light conditions and the infrared so often used by CCTV imaging. “Most CCTV cameras
use near infrared light for night-time recordings, which can make the footwear look completely different to its appearance in natural light,” Professor Gwinnett commented. “So, it was important to develop a method that will help police to quickly identify the type of shoe, how common it is, and importantly
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