After heavy intake of alcohol certain parts of a person's face warms up disproportionately, as it causes dilation of blood vessels on the surface of the skin, a study has revealed.
Researchers from Greece have now developed two new methods to automatically detect when someone has been drinking.
Georgia Koukiou from University of Patras in Greece, and his colleagues trained thermal cameras on volunteers who were drinking beer.
The software picked out 20 points on every volunteer's face and the temperature was logged.
The more alcohol the volunteers consumed, the warmer those face regions became, New Scientist reported.
When matched against a thermal database of faces of people who didn't drink, the simple approach told who was drunk and who was not.
In the second method, an algorithm was used for comparing the temperature differences in different regions of people's face.
The researchers saw that a person's nose became relatively hotter than their forehead, when their alcohol consumption increased.