A COVERT lie detection system using thermal imaging cameras and powerful software to spot tell-tale signs of deception is to be trialled at an undisclosed airport in Britain, The (London) Sunday Times has reported.
The system could be used during customs interviews and at passport control to check whether people entering the country are giving a true account of themselves.
A key element will be that people under scrutiny will not know they are being monitored for truthfulness.
The airport where it will be tested is not known but if it works it could be installed in others around Britain.
Hassan Ugail, a Professor of visual computing at the University of Bradford and who designed the system, said, "In an interview you can be talking to a person, then you basically just press a computer button and say: was this person lying or not?"
Such systems could lead to sharp improvements in security but also raise issues of privacy and misuse. They could, for example, be deployed in ethically debatable situations such as business meetings, schools or even by suspicious spouses and parents.
Ugail built his system around the observations that when people lie their brain activity rises as they work out the most plausible tale to spin.
This extra activity is reflected by tiny changes in facial expression which can be measured by a video camera linked to a computer.
Additionally, the same surges in brain activity cause corresponding changes in the patterns of blood flow around the face.
Ugail’s system is still experimental and its success rate in detecting lies is about 60-70 per cent. He believes this will rise as the system is refined.
Privacy International, a pressure group campaigning for personal privacy, has said such systems should be tightly controlled. In a policy statement it said, "We believe the CCTV trend involves a number of grave risks. A situation is developing in which CCTV surveillance is so commonplace that fundamental changes are occurring in policing, community development policy and personal privacy."