Journal of Computer Science & Systems Biology

Algorithm to Calculate Heart Rate and Comparison of Butterworth IIR and Savitzky-Golay FIR Filter

Abstract

Chatterjee A* and Roy UK

Heart Rate is an important physiological parameter for health monitoring. Heart Rate measurement with smart phone is used by many people all over the world and different applications are developed. But, there are few issues behind the proper measurement like motion, baseline drift, power line interference, low amplitude PPG, and premature ventricular contraction and noise in the signal. While capturing red contact video of fingertips, miss touch errors can produce significant variation in real result as noise gets incorporated. Similarly, high pressure on camera and low pressure on camera can produce incorrect PPG signal and therefore, mislead to incorrect result. They can be treated as noise and needs to be removed up to a level to keep up the originality of a signal to give correct BPM rate. Here, in our study we have introduced an algorithm to get rid of certain percent of miss touch errors and thereby calculate heart rate from noise free signal, accurately. Here in our study, we have focused on Non-Invasive PPG signal based Heart Rate monitoring from skin blood flow using IR light at 900 nm wavelength. We have captured contact unfocused video to capture PPG using smart phone and developed algorithm to remove some percent of touch errors and followed by noise removal with 2^nd Order Butterworth (IIR) band pass filter with frequency domain analysis and Hann Windowing for leakage reduction. We have also completed a comparative study in between Butterworth filter and Savitzky-Golay filter. The PPG is obtained from RED channel of the captured live video of smart phone camera.