By Liat Clark, Wired UK

Computer scientists have published a paper detailing how two algorithms could be used in conjunction with thermal imaging to scan for inebriated people in public places.

[partner id="wireduk" align="right"]In the paper, published in the International Journal of Electronic Security and Digital Forensics, Georgia Koukiou and Vassilis Anastassopoulos of the University of Patras in Greece detail two different algorithms they are working on that focus on data gathered from a subject's face – alcohol causes blood-vessel dilation at the skin's surface, so by using this principle as a starting point the two began to compare data gathered from thermal-imaging scans. One algorithm compares a database of these facial scans of drunk and sober individuals against pixel values from different sites on a subject's face. A similar method has been used in the past to detect infections, such as SARS, at airports – though a study carried out at the time of the 2003 outbreak warned, "although the use of infrared instruments to measure body surface temperatures has many advantages, there are human, environmental, and equipment variables that can affect the accuracy of collected data."

A second algorithm is used to map out the different areas of the face. The pair found that, when inebriated, an individual's nose tends to become warmer while their forehead remains far cooler. To use this information against the database with the first algorithm, a second algorithm was necessary to identify and differentiate between features.

The system could, the paper argues, be used to avoid embarrassing and unfounded reproaches by police officers and officials, who generally make assumptions based on behaviour and appearances alone.

Thermal imaging is already used to spy on potential criminals and was even used to see if the Occupy LSX protestors were in their tents at night at St Pauls. Practical applications like the one Koukiou and Anastassopoulos are suggesting might save police embarrassment and avoid undue disturbances. However, it might also annoy a fair few sociable late-night drinkers harmlessly going about their business while having their bodies unwittingly scanned in an intrusive breach of personal privacy.

Image: Drunk tank/Boston Public Library/CC BY-NC-ND 2.0