SPIE Newsroom 10.1117/2.1200701.0609 A pyroelectric biometric sensor system for human identification Ken Y. Hsu, Jian-Shuen Fang, Qi Hao, David J. Brady, and Bob D. Guenther A novel pyroelectric sensor system uses biometrics to extract human walking features and to provide high-identification capability for intel- ligent machines and secure systems. The pyroelectric infrared (PIR) sensor makes possible high per- formance IR radiation detection at room temperature, while cost and low power consumption make it attractive for security ap- plications. Tracking human targets with such a system has been described, 1 but little attention to date has been paid to walking, which can also be employed for purposes of identification and scene surveillance in security applications. It can also be used for for tracking multiple persons. When humans walk, the motion of various parts of the body, including the torso, arms, and legs, produces a characteristic sig- nature. Much work on motion analysis as a behavior biometric has used video cameras to stream large amounts of data from which the identity of the person of interest can be extracted in a computationally expensive way. 2, 3 A continuous-wave (CW) radar has been developed to record the signature corresponding to the walking human gait. 4 We propose a new method by which the features of motion are represented by the processed content of the temporal signal, generated by humans crossing the field of view (FOV) of the PIR sensor module . Feature representation is key to biometric recognition. From a thermal perspective, each person represents a distributed in- frared source, the distribution function of which is determined by shape and IR emissivity of the skin at every point. Com- bined with idiosyncrasies of carriage, heat will uniquely impact a surrounding sensor field. even while the subject follows a pre- scribed path. By measuring the response thus generated within the FOV of a sensor module, we can model data to create a code vector that uniquely identifies the person. We have developed two PIR feature-generating sensor systems. 5, 6 One system is analog, the other digital, and both are derived from the signals generated by humans crossing detec- tion areas. The experimental setup used for analog feature gen- Figure 1. Experimental setup for the PIR sensor-based recognition system. Figure 2. . Output signals for two individuals crossing the field of view of one sensor unit. Continued on next page