Breathing rate estimation from a non-contact biosensor using an adaptive IIR notch filter

In this paper, a non-contact method for human breathing rate estimation is discussed. The method utilises SleepMinder technology, which implements a radio-frequency Doppler radar system to capture physiological movements of the body in the form of phase modulation. To determine the breathing rate, the signals are down-converted and the baseband signals are processed. Previously reported methods used the conventional periodogram approach to estimate the breathing rate. A downside of the periodogram method is its limited capability in capturing respiration dynamics. The adaptive notch filter approach, discussed herein, provides a better respiration rate tracking performance than the periodogram approach, as demonstrated by the experimental results presented in this paper.