Systems and methods for high-pass filtering a photoplethysmograph signal

摘要

According to embodiments, systems and methods for high-pass filtering a plethysmograph or photoplethysmograph (PPG) signal are disclosed. A sensor or probe may be used to obtain a plethysmograph or PPG signal from a subject. The sensor may be placed at any suitable location on the body, e.g., the forehead, finger, or toe. The PPG signal generated by the sensor may be high-pass filtered to disambiguate certain features of the PPG signal, including one or more characteristic points. The cut-off frequency for the high-pass filter may be greater than 0.75 Hz and less than 15 Hz. The cut-off frequency for the high-pass filter may be selected to be greater than the subject's computed pulse rate. These characteristic points on the filtered PPG signal may be used to compute non-invasive blood pressure measurements continuously or on a periodic basis. For example, the time difference between two or more characteristic points in a high-pass filtered version of the generated PPG signal may be computed. The time difference may be used to compute non-invasive blood pressure measurements continuously or on a periodic basis.

主权项

1. A method for high-pass filtering a photoplethysmograph (PPG) signal used for determining a blood pressure measurement of a subject comprising:
detecting the PPG signal; computing a pulse frequency of the subject; selecting a cut-off frequency for a high-pass filter based at least in part on the computed pulse frequency, such that the cut-off frequency is approximately equal to the computed pulse frequency; filtering the detected PPG signal with the high-pass filter; identifying at least one characteristic point in the filtered PPG signal; and determining, based at least in part on the at least one identified characteristic point, the blood pressure measurement.