Simultaneous Analysis of Far Infrared Signals From Periorbital and Nostril Areas for Nonintrusive Lie Detection: Performance From Real Case Study

This paper highlights our simultaneous analysis of two-dimensional far-infrared data around the two periorbital and the nostril areas for nonintrusively evaluating the deception level of the subject. In our proposed approach, measured changes in maximum skin temperatures around two periorbital regions are converted to the change in the relative blood flow velocity. A signature of the respiration pattern is also simultaneously determined in terms of the ratio of the measured maximum and minimum temperatures in the nostril area. Our simultaneous analysis of these two far-infrared signatures is similar to the standard polygraph test in that more than one of our involuntary reflexes is examined at once. Our two-year field test study covers 18 examination tests on subjects who are suspected in involving in real crime cases in Thailand. Based on our automatic baseline classification and scoring criteria, we obtain a promising classification rate of 88.9%, which is about 10% improvement compared to our analysis using far-infrared data from either the periorbital or nostril area alone.