A new facial recognition system makes it easier and simpler for witnesses to identify suspects writes Neil Ward.
“I’d know them if I saw them again” is a common statement from witnesses who do not have the words to describe the facial features they hold in their visual memory. Eskimos might well have 20 words for snow, but we don’t have the same descriptive tools for the shape of a nose. This has made it difficult to translate an image stored in memory into a visual representation of a face that can be shared and disseminated. Until now.
The Photographic Section of the Garda Technical Bureau has acquired a new system that makes it easier and simpler for witnesses to identify suspects. Since it was introduced in mid-January the first two cases using the system have resulted in positive nominations of suspects by investigating gardaí.
The new facial recognition system, Evo-FIT, constructs facial composites of offenders by witnesses and victims of crime. It differs from the previous CD-Fit system as it utilises the recognition memory of a witness rather than recall memory, which used to necessitate the witness describing each individual feature of a face such as eyebrows, eyes, nose and mouth. It is the result of over 15 years of intensive laboratory research, and claims a suspect identification rate of about 60 per cent – approximately ten times higher than traditional methods – and is no more expensive.
Witnesses and victims select from screens of complete faces and a composite is ‘evolved’ over time. The system does not require eyewitnesses to have good recall of an offender’s face, unlike the traditional ‘feature’ methods – just to have seen it clearly is enough to create a visual likeness. The approach aims to construct the most identifiable set of internal features, the central region of the face that is important for recognition by another person later, when seen by a police officer or member of the public.
While starting to sound like an advertisement, this allows a composite to be made in many more criminal cases than previously possible. It’s also possible to create an image of the headgear the suspect might have been wearing through a large range of quirky and conservative hairstyles, hats, caps and hoods. There are tools available to improve the likeness ‘on demand’, to change the perceived age, weight, masculinity, health and other global properties of the face – the ‘holistic’ tools. It is also possible to manipulate individual features of the face including eyes, nose and mouth to order.
The witness is asked to remember the face as a whole, including the character or personality of the suspect, which helps further on in the process with the recognition of faces.
There are now six ‘facial identification officers’ in the Photographic Section to operate the system, all trained by the developer of the software, Dr Charlie Frowd of the University of Winchester.
Gardaí can make a request for an Evo-FIT directly without going through the chain of command. If a member has a witness who has seen the suspect and think they would recognise that person if they saw them again, they should speak to one of the facial identification operators. Then they go onto the portal page, fill out the interactive application form, EVO1, requesting an EvoFIT. Time is of the essence, ideally a request should be made within 24 – 48 hours of the incident.
Detective Sergeant Paul Curran, Photographic Section, Garda Technical Bureau said, “We have had very positive feedback from the images we have already created. Recently there was an attempted hi-jacking of a car. From the witness-created image of the perpetrator, we were able to create a visual image that was subsequently utilised to identify two possible suspects.”
The only details required to start the process are the race of the person and approximate age. A variety of over 60 ‘face databases’ are available for construction of offenders with different race, gender or age.
The process still begins with the cognitive interview so the witness can talk about the incident and try to visualise the suspect’s face. Additionally they are asked what they can remember about the face and to think about the persona of the person; visualising the face as a whole rather than worrying about individual features.
The witness is then shown a series of faces from the chosen database and asked to pick faces that resemble the suspect they saw. The shapes and textures are blended and are evolved to a second generation, which produce more faces based on what they have already picked.
There are approximately 20 Holistic tools to enhance the overall likeness including age, weight, masculinity, honesty, health, threatening and feature scales. They make subtle changes without distorting the face. The last element to add is the hair.
Evo-FIT then produces a composite image, which can be viewed in a number of different ways such as a plain composite, an animated image, which slightly caricatures features, or as a Perceptual Backdrop Image (PBI), which creates the illusion of viewing the image at an angle.
Detective Sergeant Curran said, “The images can be circulated locally through the stations and on the portal. For a serious case they could be used on RTE’s Crimecall and distributed in the media. The Garda Press Office put a recent Evo-FIT on the Facebook page, which resulted in hundreds of comments. It has really grabbed the public’s attention. The system is entirely portable so can be taken to any Garda station or, in the case of an elderly or very young witness, to a witness’s house.
Detective Sergeant Paul Curran said, “The Evo-FIT is a visual statement from a witness. The witness has full control of the whole process – they pick out the faces, make the changes with the holistic tools. The operator is simply helping the witness produce the image. It’s a superb system and we are really happy with it. What we have is the most up to date system that any police force has.”
The system is used by 16 police forces throughout the UK including Greater Manchester Police, Humberside Police and the Police Service of Northern Ireland (PSNI). Humberside Police’s older system, E-FIT (similar to CD-FIT), produced a suspect identification rate of 14%. Its latest evaluation of the Evo-FIT system has seen an increase in the identification of suspects to 74%.
The Garda Portal now has an Evo-FIT section, with an informative video showing how the process works – as well as the interactive form for requesting the service. n
The Photographic Section can be contacted at 01-666 2536
For full and in-depth coverage, see the current printed edition of Garda Review.