Multiple human tracking and identification with wireless distributed pyroelectric sensors

Abstract—This paper presents a wireless distributed pyroelec-tric sensor system for tracking and identifying multiple humans based on their body heat radiation. This study aims to make py-roelectric sensors a low-cost alternative to infrared video sensors in thermal gait biometric applications. In this system, the sensor field of view (FOV) is specifically modulated with Fresnel lens ar-rays for functionality of tracking or identification, and the sensor deployment is chosen to facilitate the process of data-object-associ-ation. An Expectation-Maximization-Bayesian tracking scheme is proposed and implemented among slave, master, and host modules of a prototype system. Information fusion schemes are developed to improve the system identification performance for both individ-uals and multiple subjects. The fusion of thermal gait biometric information measured by multiple nodes is tested at four levels: sample, feature, score, and decision. Experimentally, the proto-type system is able to simultaneously track two individuals in both follow-up and crossover scenarios with average tracking errors less than 0.5 m. The experimental results also demonstrate system’s po-tential to be a reliable biometric system for the verification/identifi-cation of a small group of human subjects. The developed wireless distributed infrared sensor system can run as a standalone pris-oner/patient monitoring system under any illumination conditions, as well as a complement for conventional video and audio human tracking and identification systems. Index Terms—Multiple human tracking, walker identification, pyroelectric sensor, wireless sensor network. I