Aiming to catch criminals red-footed

A computer system can spot those who are guilty by the way they walk, report our correspondents
By Stewart Tendler and Lucy Bannerman
The Times
Oct. 01, 2006

THEY may be able to wear disguises, dodge CCTV and even keep their DNA under control, but one thing will always identify criminals — their walk.

Far from relying on fingerprints or photofit, scientists now believe that an individual’s gait can give the game away.

Police have databanks of palm prints, ear prints and handwriting at their disposal, as well facial recognition systems that can match fugitive faces with those in a crowd. But the next step could be swagger surveillance.

For more than ten years, scientists have been working on a computer system that can analyse the movements of criminals caught on CCTV and compare them with those of a suspect. The system works on the premise that every individual has a signature walking style.

The technique is still in its infancy but has been employed in high-profile cases. Swedish police successfully used it three years ago to identify a robber involved in a bank raid in which a customer was killed. Officers investigating the murder of Anna Lindh, the Swedish Foreign Minister, in 2003 asked experts to examine the walk of their suspect, Mijailo Mijailovic. Their efforts were not needed — Mijailovic confessed — but the case highlighted the technique’s potential.

In Britain scientists backed by the MoD and a £500,000 research grant are working on “automatic gait recognition”, which will allow police and courts to compare images captured on CCTV with the walk of a suspect.

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Mark Nixon, of the Southampton University department of electronics and computing, said that studies showed everyone has a distinct walk. This was because of subtle differences in muscle strength, tendon and bone length, bone density, visual acuity, co-ordination skills, experience, body mass, centre of gravity, muscle or bone damage, physiological conditions, and a personal walking “style”.

He said that it was very difficult for someone to disguise the way they walked, and they could still be identified whether casually sauntering up to the bankteller or sprinting from the scene of the crime.

Professor Nixon’s team believes that gait recognition has advantages over facial mapping. “Gait recognition could have significant implications for police. In the James Bulger case you could see the boys walking away but not their faces,” he said.

Professor Nixon said that research showed that people would recognise someone they knew with 80 per cent confidence. The team has built up a bank of images of data on volunteers to measure the differences in the way people move and to test out their theories. The volunteers walk through a biometric tunnel and have their movements caught.

It is hoped that criminals could be made to walk through similar tunnels to make identifications. Professor Dixon said: “It would have been a pipe dream ten years ago but now computers are faster and memory is a lot cheaper to buy.”

Eventually a national databank will be created to demonstrate to courts that individuals do walk differently and that the evidence of identification is safe to use as evidence.

Work is also being done on the techniques in China, Australia, Japan and the United States, where scientists have been experimenting with radar guns, similar to those used by police to track speeding cars. The US system sends out a pulse of radar energy and receives the signals reflected off objects. As a person walks the radar signals change.

The system can recognise and capture the different patterns during natural walking movements. The movements create an individual radar signature and can be replayed in the form of matchstick men.

NOWHERE TO RUN
# Many countries are moving towards biometric passports but the technology has difficulty recognising bald men, black people and those with brown eyes

# Britain has one of the largest DNA databases in Europe. In January the Home Office said police had solved 88 murders because of DNA testing

# This year Yeovil became the first British town to install fingerprint scanners in pubs and clubs to identify potential troublemakers

# Plans have been mooted for a database of footprints to help police to search for links between suspects’ shoes and prints from unsolved crimes












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