Device and method for determining a respiration rate of a subject

Abstract

The present invention relates to a device, system and method for determining a respiration rate of a subject. The device presented comprises an input interface for obtaining a red and/or an infrared photoplethysmography, PPG, signal, a feature signal unit configured to extract a first sequence of features from the PPG signal and to generate a first feature signal from said sequence of features, a resampling unit configured to resample with a resampling function the first feature signal to yield a resampled signal with a constant sampling rate and/or to resample a first derivative to yield a resampled first derivative with a constant sampling rate, a transformation unit configured to calculate a Fourier transform of the resampled signal to yield a transformed resampled signal or to calculate a Fourier transform of the resampled first derivative to yield a transformed resampled first derivative, and an extraction unit configured to extract from the transformed resampled signal a first respiration rate or from the transformed resampled first derivative the first respiration rate, wherein the first sequence of features is a sequence of phases of the first harmonic of a heart beat of the subject with respect to a start of the heart beat and wherein the first feature signal corresponds to the sequence of phases.