TRACKING MECHANISM FOR HEART RATE MEASUREMENTS

摘要

Heart rate monitors are plagued by noisy photoplethysmography (PPG) data, which makes it difficult for the monitors to output a consistently accurate heart rate reading. Noise is often caused by motion. Using known methods for processing accelerometer readings that measure movement to filter out some of this noise may help, but not always. The present disclosure describes an improved front-end technique (time-domain interference removal) based on using adaptive linear prediction on accelerometer data to generate filters for filtering the PPG signal prior to tracking the frequency of the heartbeat (heart rate). The present disclosure also describes an improved back-end technique based on steering the frequency of a resonant filter in order to track the heartbeat. Implementing one or both of these techniques leads to more accurate heart rate measurements.

主权项

1. A method for extracting a frequency of a heartbeat signal present within an input signal generated by one or more sensors using a structure configured to implement a first filter and a second filter, the first filter and the second filter being filters that have a frequency F_RES at which the amplitude of their outputs are substantially equal and for which, above the frequency F_RES, the amplitude of the first filter becomes larger than the amplitude of the second filter, and, below the frequency F_RES, the amplitude of the second filter becomes larger than the amplitude of the first filter, the method comprising steps of:
a) determining an amplitude of an output generated by the first filter in response to the first filter receiving the input signal and one or more filter control parameters; b) determining an amplitude of an output generated by the second filter in response to the second filter receiving the input signal and the one or more filter control parameters; c) updating the filter control parameters based on the amplitudes of steps a) and b) and proceeding to step a); d) determining the frequency of the heartbeat signal based on the one or more filter control parameters.