Systems and methods for variable filter adjustment by heart rate metric feedback

Patent metadata

Field	Value
Publication number	US-9801552-B2
Application number	US-201214124465-A
Country	US
Kind code	B2
Filing date	Jul 25, 2012
Priority date	Aug 2, 2011
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A physiological signal processing system for a physiological waveform that includes a cardiovascular signal component provides a variable high pass filter that is responsive to the physiological waveform, and that is configured to high pass filter the physiological waveform in response to a corner frequency that is applied. A heart rate metric extractor is responsive to the variable high pass filter and is configured to extract a heart rate metric from the physiological waveform that is high pass filtered. A corner frequency adjuster is responsive to the heart rate metric extractor and is configured to determine the corner frequency that is applied to the variable high pass filter, based on the heart rate metric that was extracted. Analogous methods may also be provided.

First claim

What is claimed is:

1. A physiological signal processing system comprising:
a physiological sensor that is configured to generate a physiological waveform that includes cardiovascular and pulmonary signal components therein;
a variable high pass filter and a variable low pass filter that are responsive to the physiological waveform and that are configured to high pass and low pass filter, respectively, the physiological waveform in response to at least one corner frequency that is applied thereto;
a heart rate metric extractor that is coupled to an output of the variable high pass filter and is responsive to the variable high pass filter and that is configured to extract a heart rate metric from the cardiovascular signal component of the physiological waveform that is output from the variable high pass filter responsive to high pass filtering the physiological waveform;
a respiration rate metric extractor that is coupled to an output of and is responsive to the variable low pass filter and that is configured to extract a respiration rate metric from the pulmonary signal component of the physiological waveform that is output from the variable low pass filter responsive to low pass filtering the physiological waveform; and
a corner frequency adjustor that is responsive to the heart rate metric extractor and that is configured to determine the at least one corner frequency that is applied to the variable high pass filter and the variable low pass filter from the heart rate metric that was extracted based on the output from the variable high pass filter.

2. A physiological signal processing system for a physiological waveform that includes a cardiovascular signal component therein, the physiological signal processing system comprising:
a variable high pass filter that is responsive to the physiological waveform and that is configured to high pass filter the physiological waveform in response to a corner frequency that is applied thereto;
a heart rate metric extractor that is coupled to an output of the variable high pass filter and is responsive to the variable high pass filter and that is configured to extract a heart rate metric from the cardiovascular signal component of the physiological waveform that is output from the variable high pass filter responsive to high pass filtering the physiological waveform; and
a corner frequency adjustor that is responsive to the heart rate metric extractor and that is configured to determine the corner frequency that is applied to the variable high pass filter from the heart rate metric that was extracted based on the output from the variable high pass filter.

3. A physiological signal processing system according to claim 2 wherein the physiological waveform comprises an electrical physiological waveform including an electroencephalogram (EEG), an electrocardiogram (ECG) and/or a radio frequency (RF) waveform, an electro-optical physiological waveform including a photoplethysmograph (PPG) waveform, an electro-photoacoustic waveform including a photoacoustic waveform, an electro-mechanical physiological waveform including an auscultation waveform, a piezo sensor waveform and/or an accelerometer waveform, and/or an electro-nuclear physiological waveform.

4. A physiological signal processing system according to claim 2 wherein the variable high pass filter comprises a single high pass filter having an adjustable corner frequency.

5. A physiological signal processing system according to claim 2 wherein the variable high pass filter comprises a plurality of high pass filters, a respective one of which includes a different value of the corner frequency, and wherein the corner frequency adjustor is configured to select one of the plurality of high pass filters that corresponds to the corner frequency that is determined.

6. A physiological signal processing system according to claim 2 wherein the variable high pass filter comprises a variable digital high pass filter having a plurality of delay taps and wherein the corner frequency corresponds to a number of the plurality of delay taps that are selected to filter the physiological waveform.

7. A physiological signal processing system according to claim 6 wherein the corner frequency adjustor comprises a mapping system that is configured to map the heart rate metric that is extracted from the physiological waveform that is filtered into the number of the delay taps that are selected to high pass filter the physiological waveform.

8. A physiological signal processing system according to claim 2 wherein the corner frequency adjustor is configured to reduce locking on an erroneous heart rate metric.

9. A physiological signal processing system according to claim 2 wherein the corner frequency adjustor is configured to initially set a predetermined corner frequency corresponding to a predetermined heart rate prior to determining the corner frequency that is applied to the variable high pass filter from the heart rate metric.

10. A physiological signal processing system according to claim 9 wherein the predetermined heart rate is a resting heart rate.

11. A physiological signal processing system according to claim 9 wherein the corner frequency adjustor is configured to initially set the predetermined corner frequency corresponding to the predetermined heart rate until the heart rate metric extractor locks on a heart rate in the physiological waveform.

12. A physiological signal processing system according to claim 9 wherein the corner frequency adjustor is configured to reset the predetermined corner frequency corresponding to the predetermined heart rate in response to determining that the physiological sensor is no longer responsive to a source of the physiological waveform.

13. A physiological signal processing system according to claim 2 wherein the corner frequency adjustor is configured to set a predetermined corner frequency corresponding to a predetermined heart rate in response to determining that the physiological sensor is not responsive to a source of the physiological waveform.

14. A physiological signal processing system according to claim 2 wherein the corner frequency adjustor is configured to determine the corner frequency that is applied to the variable high pass filter from the heart rate metric by applying a margin to the heart rate metric.

15. A physiological signal processing system according to claim 2 wherein the variable high pass filter includes a gradual filter transition band.

16. A physiological signal processing system according to claim 2 further comprising:
a physiological metric assessor that is responsive to the heart rate metric extractor and that is configured to process the heart rate metric to generate at least one physiological assessment.

17. A physiological signal processing system according to claim 2 , wherein the corner frequency adjustor is configured to determine the at least one corner frequency that is applied to the variable high pass filter based on the heart rate metric independent of a respiration rate metric.

18. A physiological signal processing method for a physiological waveform that includes a cardiovascular signal component therein, the physiological signal processing method comprising:
high pass filtering the physiological waveform in response to an adjustable high pass filter corner frequency;
extracting a heart rate metric from the cardiovascular signal component of the physiological waveform that is output from the high pass filtering; and
determining the adjustable high pass filter corner frequency that is applied

Assignees

• Romesburg Eric Douglas
• Valencell Inc

Inventors

• Romesburg Eric Douglas

Classifications

• A61B5/0205

  Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition · CPC title

• A61B5/0095 Primary

  by applying light and detecting acoustic waves, i.e. photoacoustic measurements · CPC title

• A61B5/0245

  by using sensing means generating electric signals, {i.e. ECG signals} · CPC title

• A61B5/0059

  using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455) · CPC title

• A61B5/7278

  Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals · CPC title