Giving crime the 'evo': catching criminals using EvoFIT facial composites
Charlie D. Frowd*
1
, Peter J.B. Hancock
2
, Vicki Bruce
3
, Alex H. McIntyre
2
, Melanie Pitchford
4
,
Rebecca Atkins
1
, Andrew Webster
5
, John Pollard
6
, Beverley Hunt
7
, Emma Price
7
, Sandra Morgan
7
,
Adrian Stoika
8
, Romeo Dughila
9
, Sergiu Maftei
9
and Gabriel Sendrea
9
1
Department of Psychology, University of Central Lancashire, Preston, UK
2
Department of Psychology, University of Stirling, Stirling, UK
3
School of Psychology, Newcastle University, Newcastle, UK
4
Department of Psychology, Lancaster University, Lancaster, UK
5
Force Major Investigation Team, Lancashire constabulary, UK
6
Family Support Unit, Lancashire constabulary, UK
7
Forensic Services Unit, Derbyshire Constabulary, UK
8
NASA Jet Propulsion Laboratory, NASA, USA
9
Forensic Department of Iasi County Police Inspectorate, Romania
*Corresponding author: Dr Charlie Frowd, Department of Psychology, University of Central
Lancashire, Preston PR1 2HE. Email: cfrowd@uclan.ac.uk. Phone: (01772) 893439.
Abstract
Facial composites are traditionally made by witnesses
and victims describing and selecting parts of criminals’
faces, but this method is hard to do and has been shown
to be generally ineffective. We have been working on an
alternative system called EvoFIT for the past 12 years.
Much of the development for this system has been carried
out in the laboratory but, more recently, police forces
have been formally evaluating it in criminal
investigations. The current paper describes three of these
police audits. It was found that EvoFIT composites made
from real eyewitnesses led to an overall arrest in 23.4%
of cases, which is similar to a 24.5% correct naming level
found by laboratory research. System performance
therefore appears to be effective both using simulated
testing procedures and in the hands of the intended user.
0. Warning about content
This technical paper contains descriptions of criminal
offences. Some of these offences were against young
people and are very serious. While individual case studies
are not described in detail here, some readers may still
find them disturbing; these readers may prefer to skip
over the case studies: they are clearly labelled.
1. Introduction
Witnesses and victims may be asked to construct a picture
of a person they have seen commit a crime. This picture is
known as a facial composite and can help the police to
detect the perpetrator. Various techniques are available to
produce these images. Traditionally, eyewitnesses
describe the face in detail and build the composite by
selecting individual facial features: hair, eyes, nose,
mouth, etc. However, we do not perceive faces in such a
piecemeal fashion, but instead process it more as a
complete entity [1]. For this reason, face construction
using the ‘feature’ approach often results in poor quality
images, especially when carried out several days after the
face had been originally seen [2], the normal situation for
eyewitnesses.
More recent so-called ‘holistic’ approaches [2-4] have
attempted to overcome this problem using interfaces that
require focus on the face as a whole. In essence, users
repeatedly select complete faces from screens of
alternatives, with cycles of ‘breeding’ in between, to
allow a composite to be ‘evolved’. The approach has the
potential to allow construction when a witness has seen
the face, but cannot describe it in detail. It is in this
situation that the traditional methods cannot be used
effectively, since they require a good description for
locating subsets of features (for presentation to the
witness). In contrast, the ‘holistic’ systems only require
fairly general information: age, gender, race and hair.
The focus on the current paper is on one of these
methods, EvoFIT. This system has been the focus of
considerable research and development in the laboratory,
and some of this work has been presented at previous
BLISS conferences [5,6]. For three years now, EvoFIT
has also been the subject of formal police field trials.
These have explored the effectiveness of the system when
2010 International Conference on Emerging Security Technologies
978-0-7695-4175-4/10 $26.00 © 2010 IEEE
DOI 10.1109/EST.2010.38
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