BREATHING AND HEARTBEAT FEATURE EXTRACTION AND VICTIM DETECTION

• US 20150223701A1
• Filed: 02/09/2015
• Published: 08/13/2015
• Est. Priority Date: 02/10/2014
• Status: Active Application

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Ghaemi, Hirad, Lux, James P.
• Application Number:
  US14/617,767
• Publication Number:
  US 20150223701A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0475 Special features of memory means, e.g. removable memory cards
• CPC Class Codes: A61B 2562/0228 Microwave sensors
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

Systems and methods for detecting biometrics using a life detecting radar are disclosed. Life detecting radars can include transmit antennas configured to transmit continuous microwave (“CW”) radio signals that reflect back upon making contact with various objects. The life detecting radars can identify victims by analyzing data with respect to a victim'"'"'s breathing and heartbeat patterns. In some embodiments, to identify victims, the return signal may be split into a heartbeat band and a breathing band using bandpass filtering. The life detecting radar system may perform parameter estimation for the breathing band and/or the heartbeat band using a non-least squares process (NLS). The life detecting radar system may analyze breathing and heartbeat results based on the heartbeat FM frequency and the breathing center frequency to identify victims.

Claims

1. An integrated microwave sensor module comprising:

a transmitter unit comprising a variable frequency microwave source connected to at least one transmitter unit amplifier, where;

the variable frequency microwave source is configured to generate at least one continuous wave (“

CW”

) transmit signal based upon at least one frequency control signal received from a microcontroller unit; and

the at least one transmitter unit amplifier is configured to receive and amplify the at least one CW transit signal;

a receiver unit configured to receive at least one return signal and utilize a cancellation path to cancel contributions to the return signal that are not the result of reflections from a target;

a microcontroller unit configured to communicate with the transmitter and receiver units comprising;

a processor;

a memory containing a microcontroller application, wherein the microcontroller application configures the processor to;

split the return signal into a heartbeat band and a breathing band using bandpass filtering;

perform parameter estimation for the breathing band using a non-least squares process (NLS);

perform parameter estimation for the heartbeat band using an NLS process;

analyze breathing and heartbeat results based on the heartbeat FM frequency and the breathing center frequency; and

output detected targets based on analysis.

2. The integrated microwave sensor module of claim 1, wherein a NLS process fits a complex input to a frequency modulated (FM) model.

3. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to low pass filter and decimate the return signal.

4. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove a linear trend from the return signal using a linear least square fitting in the data.

5. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove signals that are out of band.

6. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to identify and remove 2^nd and 3^rd harmonics from a list of detected frequencies of the breathing band.

7. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove harmonics of breathing signals that appear in the heart band.

8. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove out of band heartbeat signals from the heart band by removing targets whose center frequency is out of an assigned bandwidth.

9. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove targets whose FM frequency is out of a particular FM frequency range.

10. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove targets whose relative amplitude with respect to a maximum in the heartbeat band is below a certain threshold based on a dynamic range for detected targets.

11. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove targets whose relative amplitude with respect to a maximum in the breathing band is below a certain threshold based on a desired dynamic range for detected targets.

12. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to remove heart signals whose relative amplitude with respect to breathing is large within a certain threshold.

13. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to match breathing results with heartbeat results based on the heartbeat FM frequency and breathing center frequency.

14. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to calculate reliability factors for the heartbeat band and the breathing band by using corresponding signal to noise ratio “

SNR”

values.

15. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to compare a plurality of signals received from a plurality of receivers to identify false targets.

16. The integrated microwave sensor module of claim 1, wherein the microcontroller application further configures the processor to compare results from each of a plurality of received signals to identify false targets.

17. A method of detecting a target using a life detecting radar, the method comprising:

propagating at least one beam using a continuous wave transmit signal set at a plurality of frequencies, where the at least one beam illuminates at least one sensing area using at least one transmit unit;

receiving a return signal associate with reflections of the at least one transmit signal from objects within the at least one sensing area using at least one receive antenna;

receiving the return signal from the at least one receive antenna using a life detecting radar system;

splitting the return signal into a heartbeat band and a breathing band using bandpass filtering;

performing parameter estimation for the breathing band using a non-least squares process (NLS);

performing parameter estimation for the heartbeat band using an NLS process;

analyzing breathing and heartbeat results based on the heartbeat FM frequency and the breathing center frequency; and

outputting detected targets based on analysis.

18. The method of claim 17, wherein a NLS process fits a complex input to a frequency modulated (FM) model.

19. The method of claim 17, further comprising applying a low pass filter to the return signal.

20. The method of claim 17, further comprising removing a linear trend from the return signal using a linear least square fitting in the data.