Neural networks for identifying drunk persons using thermal infrared imagery

• Neural networks are tested on infrared images of faces for discriminating intoxicated persons.
• Mainly the face forehead changes thermal behaviour with alcohol consumption.
• Neural networks present high discrimination performance when trained on the person's forehead.
• Intoxicated person identification is achieved using only the drunk person infrared image.
• Small neural structures present better generalisation performance.

Neural networks were tested on infrared images of faces for discriminating intoxicated persons. The images were acquired during controlled alcohol consumption by forty-one persons. Two different experimental approaches were thoroughly investigated. In the first one, each face was examined, location by location, using each time a different neural network, in order to find out those regions that can be used for discriminating a drunk from a sober person. It was found that it was mainly the face forehead that changed thermal behaviour with alcohol consumption. In the second procedure, a single neural structure was trained on the whole face. The discrimination performance of this neural structure was tested on the same face, as well as on unknown faces. The neural networks presented high discrimination performance even on unknown persons, when trained on the forehead of the sober and the drunk person, respectively. Small neural structures presented better generalisation performance.