Review of signal processing applications of Pyroelectric Infrared (PIR) sensors with a focus on respiration rate and heart rate detection

The article reviews signal processing applications of Pyroelectric Infrared (PIR) sensors with the main focus on the respiration and pulse rate detection. Respiration and pulse rates are vital signs that are routinely measured by healthcare providers to assess a human body's basic functions. In this paper, we review non-contact human respiratory rate and heart rate (pulse) estimation methods using the low-cost, contact-free, and non-invasive Pyroelectric Infrared (PIR) sensor. The time-varying sensor signal generated by the chest and subtle head movements are used to infer the respiratory rate and the heart rate, respectively. The PIR sensor can be mounted on the head rest of a chair or placed near a bed and can continuously estimate both the respiratory rate and the heart rate of a resting person at the same time. Experimental results indicate that a positive correlation higher than 95% between the heart rate estimates and the pulse oximeter measurements is achieved in our datasets. Similarly, a correlation coefficient of 95% is also achieved between the PIR-based respiratory rate estimates and the respiratory chest movements.