text: Memories of drunken escapades may make us blush, but now a computer can use similar facial flushes to recognise people who have had one drink too many. Greek researchers created the algorithm, which determines a person’s state of intoxication by looking at the temperature of their face - especially the forehead and nose. And they say the technology could one day be installed in cars to spot drink drivers and stop them starting the ignition. Researchers from the University of Patras took thermal infrared photographs of 41 volunteers’ faces, before and after drinking four glasses of wine. The scientists then used artificial neural networks to compare the sober (left) and drunken images (right) pixel-by-pixel (a single pixel is shown above the left eyebrow) Researchers from the University of Patras took thermal infrared photographs of 41 volunteers’ faces, before and after drinking four glasses of wine. Thermographic cameras detect radiation in the infrared range of the spectrum and create images of the radiation, where warm areas are shown red and cooler areas, blue, for example. Many people feel warmer and have hot flushes after drinking alcohol, caused by the drug affecting brain chemistry and the circulatory system. When alcohol is absorbed into the blood stream it increases heart rate and blood pressure and blood vessels open wide to allow for more rapid flow, which causes some people to flush. Alcohol also affects the hypothalamus, which regulates the body's temperature. Thermographic cameras detect radiation in the infrared range of the spectrum and create images of the radiation, where warm areas are shown red and cooler areas, blue, for example. In the study, the researchers found that the temperature of the forehead and to a lesser extent, the nose, is the best indication of a person’s drunken state and built an algorithm to recognise intoxication with 90% accuracy. While the alcohol got some volunteers more tipsy than others, they all had a blood alcohol content of at least 50 milligrams of alcohol in every 100 millilitres of blood. This figure is the drink driving limit in Scotland as well as most European countries – but slightly below the English and Welsh limit of 80 milligrams of alcohol per 100 millilitres of blood. The scientists then used artificial neural networks to compare the sober and drunken images pixel-by-pixel. They found that the temperature of the forehead, and to a lesser extent the nose, is the best indication of a person’s drunken state and built an algorithm to recognise intoxication with 90 per cent accuracy. The scientists wrote in the study, published in the journal Forensic Journal International: ‘It was found that it was mainly the face forehead that changed thermal behaviour with alcohol consumption.' The algorithm worked even on faces that it hadn’t been trained on, and without comparing them to images of people when they were sober. Many people feel warmer and have hot flushes after drinking alcohol, caused by the drug affecting brain chemistry and the circulatory system. They found the temperature of the forehead and the nose is the best indication of a person’s drunken state, and built an algorithm to recognise intoxication with 90% accuracy. Red squares in these images of two drunk people reveal the areas which can be used to discriminate between drunk and sober most effectively . A sober participant's face is shown left, while the same participant's face is pictured right after he had been drinking. The algorithm worked even on faces that it hadn’t been trained on, and without comparing them to images of people when they were sober . When alcohol is absorbed into the blood stream it increases heart rate and blood pressure and blood vessels open wide to allow for more rapid flow, which causes some people to flush. Alcohol also affects the hypothalamus, which regulates the body's temperature. Just three hours behind the wheel at night can make motorists drive as badly as if they were drunk, scientists claim. Driver tiredness after a few hours has the same effect as being over the drink-driving limit, a 2011 study revealed. Even two hours of motorway driving in the dark can affect performance so severely it is the same as having a couple of drinks. It's estimated that one-fifth of all traffic accidents are due to sleepiness behind the wheel and one in three people admit to nodding off while driving at night. The researchers hope their technology could be used by the police to spot intoxicated people who might start trouble at football matches, for example and say it could be installed in cars and lorries to spot potential drink drivers. It could perhaps work in tandem with other technology to stop a car from being able to be driven. Scientists in Germany are already working on a way to stop drink drivers getting behind the wheel by analysing their speechm for example. They announced in December they have created the first library of drunk speech patterns, which could be used to predict drunkenness by listening for vocal cues. Called the Alcohol Language Corpus, the database was made by researchers from Ludwig Maximilian University of Munich and the Institute of Legal Medicine between 2007 and 2009 by giving people too much alcohol to drink, before recording conversations conducted in a stopped car, where the drunk person was sitting in the passenger seat. There are currently conversations from 162 German men and women in the publicly-available audio database. While the alcohol got some more tipsy than others, all the volunteers in the study had a blood alcohol content of 50 milligrams of alcohol in every 100 millilitres of blood, which is the drink driving limit in Scotland as well as most European countries. A stock image illustrating drink driving is shown . The researchers hope their technology could be used by the police to spot intoxicated people who might start trouble at football matches, for example and say it could be installed in cars and lorries to spot potential drink drivers. Currently, breathalyzers (pictured) are used to measure alcohol content . From this, an algorithm capable of detecting whether someone is drunk by listening in on slurring speech patterns, was created by computer scientists at Queens College and Columbia University. They found they could detect drunken speech patterns much like identifying an accent. Drunken speech hallmarks include stammering and stuttering. Voices also tend to rise in pitch and words begin to slur, they said. It is hoped that the software could be used alongside devices such as locks and immobilisers to make it impossible for people to drive when drunk – perhaps by asking them a few questions while analysing the driver’s voice. ‘The cars themselves could listen to the driver, detect that the potential driver is intoxicated, and prevent the car from starting,’ the researchers explained.
target: Researchers from the University of Patras, in Greece created the algorithm .
  Determines a person's state of intoxication by their facial temperature .
  Analysing the forehead and nose gives an accuracy rate of 90 per cent .
  Experts say system could one day be used by the police, and even in cars .