Systems and methods for non-contact monitoring of ballistocardiogram, photoplethysmogram, blood pressure and abnormal heart rhythm

Patent metadata

Field	Value
Publication number	US-11045095-B2
Application number	US-201716083052-A
Country	US
Kind code	B2
Filing date	Mar 8, 2017
Priority date	Mar 11, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

Various embodiments of systems and methods for tracking ballistocardiogram, photoplethysmogram, blood pressure and abnormal heart rhythm based on optical imaging of a human body are disclosed. Ballistocardiogram and photoplethysmogram signals from a similar region of the human body are simultaneously obtained, and the time delay between the two signals is used to determine the blood pressure of the subject, together with other physiological parameters of the subject, including gender, age, weight, height, heart rate, stroke volume, blood pressure and abnormal heart rhythm obtained using other methods.

First claim

What is claimed is:

1. A method for monitoring an individual having a body part, the method comprising:
receiving a set of sequential video frames of the body part of the individual at a controller, the set of sequential video frames captured using a single camera;
defining a region of interest of the body part in a first video frame of the set of sequential video frames, the region of interest including a body feature;
tracking motion of the body feature over the set of sequential video frames using the controller;
generating a ballistocardiogram (BCG) waveform based on the set of sequential video frames that defines BCG signals associated with the motion of the body feature using the controller, wherein to generate the BCG waveform, the controller, for each frame of the set of sequential video frames, averages vertical components of point locations over all detected feature points of the region of interest plotted against time; and
generating a photoplethysmogram waveform based on an image intensity averaged over the region of interest for each frame in the set of sequential video frames and plotted against time using the controller.

2. The method of claim 1 , wherein the BCG waveform includes a velocity BCG waveform and an acceleration BCG waveform corresponding respectively to first and second temporal derivatives calculated from the BCG waveform.

3. The method of claim 1 , further comprising: generating a pulse transit time based on a relative time shift between the BCG waveform and the photoplethysmogram waveform.

4. The method of claim 3 , further comprising: determining a blood pressure for the individual from at least one of the pulse transit time, cardiac output, peripheral resistance, vessel elasticity, or blood volume.

5. The method of claim 4 , further comprising:
determining a heart rate for the individual from the BCG waveform or the photoplethysmogram waveform;
determining a stroke volume for the individual from the BCG waveform; and
determining the cardiac output from the heart rate and the stroke volume.

6. A system for monitoring an individual having a body part, the system comprising:
a camera disposed relative to the body part of the individual that captures a set of sequential video frames of the body part of the individual; and
a controller in communication with the camera, the controller adapted to generate a ballistocardiogram waveform and a photoplethysmogram waveform from the set of sequential video frames, the ballistocardiogram waveform generated from a vertical displacement of a body feature within a defined region of interest of the body part and tracked over the set of sequential video frames, the photoplethysmogram waveform generated based on an image intensity averaged over the region of interest for each frame in the set of sequential video frames and plotted against time.

7. The system of claim 6 , wherein the controller generates a pulse transit time based on a relative time shift between the ballistocardiogram waveform and the photoplethysmogram waveform.

8. The system of claim 7 , wherein the controller determines a blood pressure for the individual from the pulse transit time.

9. The system of claim 6 , wherein the controller determines a Premature Ventricular Contraction (PVC) based on the ballistocardiogram waveform and the photoplethysmogram waveform from the set of sequential video frames.

10. The system of claim 6 , wherein the ballistocardiogram waveform includes a velocity ballistocardiogram waveform and an acceleration ballistocardiogram waveform.

11. The system of claim 6 , wherein the image intensity is averaged for a first color channel and a second color channel.

Assignees

• Univ Arizona State
• Tao Nongjian
• Shao Dangdang

Inventors

• Tao Nongjian
• Shao Dangdang

Classifications

• A61B5/02416

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title

• A61B5/0205 Primary

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

• A61B5/02125

  of pulse wave propagation time · CPC title

• A61B5/0077

  Devices for viewing the surface of the body, e.g. camera, magnifying lens · CPC title

• G06T7/20

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title