Forehead thermal signature extraction in lie detection

Area of Science:

• Psychophysiology
• Biomedical Engineering
• Forensic Science

Background:

• Facial thermography has shown potential for lie detection, primarily using the periorbital region.
• Previous methods focused on thermal signatures around the eyes.

Purpose of the Study:

• To investigate the forehead as a novel source of psycho-physiological information for lie detection.
• To develop a method for monitoring stress-induced thermal changes in the forehead.

Main Methods:

• A segmentation method based on active contours was developed to create a virtual forehead probe.
• This probe monitors thermal radiation over supraorbital vessels to assess stress levels.
• Thermal videos from 38 subjects in a mock crime scenario were analyzed.

Main Results:

• Increased corrugator muscle activity during stress elevates forehead cutaneous temperature due to increased blood flow.
• The developed forehead thermal signal achieved a 76.3% success rate in classifying deceptive states.
• The forehead channel demonstrates significant promise as a new indicator in lie detection.

Conclusions:

• The forehead offers a viable new channel for psycho-physiological monitoring in deception detection.
• The active contours-based segmentation method effectively captures relevant thermal signatures.
• This approach advances the application of facial thermography in forensic and security contexts.