A Motion Heart-Rate Monitor Watch with Improved Grey Differential Equation Model Based on Reflective Photoplethysmography
With the advantage of noninvasive measurement, reflective photoplethysmography (PPG) has been adopted by a group of gadgets to estimate heart rate (HR) from the wrists. Challenges include PPG artifacts reduction and comfortable type design. Aimed at improving the accuracy of measurement during wrist movements such as handshake or exercises, in this paper, a motion HR monitor watch has presented. The work mainly focused on two categories: the HR extraction algorithm derived from grey differential equation model (abbreviated as GM(1, 1) model) combined with acceleration model and the enhanced hardware structure designed with 523 nm green leds. The tests have been carried out and results analysis show high correlation among the values measured respectively from this watch, HR chest belt (taken as HR gold standard) and commercial motion HR watch in various intensities of exercises.