System and method for extracting physiological data using ultra-wideband radar and improved signal processing techniques

• US 7,725,150 B2
• Filed: 06/04/2003
• Issued: 05/25/2010
• Est. Priority Date: 06/04/2003
• Status: Active Grant

• Current Assignee: LifeWave Biomedical, Inc.
• Original Assignee: LifeWave, Inc.
• Inventors: Tupin, Joe Paul Jr., Rollins, Richard Jensen, Van Rooyen, Robert Martinez
• Primary Examiner(s): Casler; Brian
• Assistant Examiner(s): KISH, JAMES M
• Application Number:
  US10/456,290
• Publication Number:
  US 20040249258A1
• Time in Patent Office: 2,547 Days
• Field of Search: 600/407, 600/430, 382/128
• US Class Current: 600/407
• 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 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• 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 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7253 characterised by using transforms
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband

Abstract

Disclosed is a variant of ultra-wide band (UWB) radar known as micropower impulse radar (MIR) combined with advanced signal processing techniques to provide a new type of medical imaging technology including frequency spectrum analysis and modern statistical filtering techniques to search for, acquire, track, or interrogate physiological data. Range gate settings are controlled to depths of interest within a patient and those settings are dynamically adjusted to optimize the physiological signals desired.

Claims

1. A process employing ultra wideband radar return signals to extract physiological data from one or more bodily organs or physiological processes of a patient, said process comprising:

generating a baseband pulse train;

transmitting an emitted signal from a first antenna as an ultra-wide band spectrum signal, wherein the emitted signal comprises a series of low voltage, short-duration pulses triggered by the baseband pulse train;

outputting a delayed version of the baseband pulse train from a delay range comprising an electronically controlled range gate;

receiving reflections of the emitted signal at a receiver connected to a second antenna, wherein the receiver is triggered by the delayed version of the baseband pulse train;

processing the reflections received by the receiver to generate a first matrix of time-sampled reflection values at various depths;

converting the first matrix of time-sampled reflection values into a second matrix and extracting physiological data from the second matrix using frequency spectrum analysis and statistical filtering.

2. The process of claim 1 wherein the step of outputting a delayed version of the baseband pulse train comprises outputting a delayed version of the baseband pulse train in range gate mode, wherein the delayed version of the baseband pulse train is configured to trigger the receiver to collect reflections at one or more of a subset of said depths.

3. The process of claim 1 wherein the step of outputting a delayed version of the baseband pulse train comprises outputting a delayed version of the baseband pulse train in range finder mode, wherein the delayed version of the baseband pulse train is configured to trigger the receiver to collect reflections across a range of said depths.

4. The process of claim 1 further comprising operating on said second matrix to suppress certain high-strength reflection signals and amplify signals representing motion within said patient.

5. The process of claim 1, wherein the processing step includes low-pass filtering, said low pass filtering passing frequencies up to 5 Hz, and minimizing the potential of aliasing prior to generating the first matrix of time-sampled reflection values.

6. The process of claim 1, wherein the processing step includes low-pass filtering, said low pass filtering passing frequencies up to 200 Hz, and minimizing the potential of aliasing prior to generating the first matrix of time-sampled reflection values.

7. The process of claim 1, further comprising digitizing the reflections of the emitted signal received by the receiver from analog to digital into a series of discrete numerical values representing the amplitudes of said reflections of the emitted signal.

8. The process of claim 4, wherein the first matrix is a two-dimensional matrix of time-sampled reflection values from various depths.

9. The process of claim 8 wherein the two-dimensional matrix stores a matrix of reflections of the emitted signal at various depths and times.

10. The process of claim 8 wherein the depth of said various depths within the patient from which said time-sampled reflection values are collected is fixed and a number of samples of said time-sampled reflection values are collected at said fixed depth over a period of time.

11. The process of claim 8 wherein the depth of said various depths within the patient from which time-sampled reflection values are collected is varied over a finite range of said depths of interest and samples of said time-sampled reflection values are collected at a plurality of said depths.

12. The process of claim 1, wherein the step of converting the first matrix of time-sampled reflections values into a second matrix comprises reducing data from said first matrix.

13. The process of claim 12 wherein said reducing includes the step of averaging values of said time-sampled reflection values to reduce the volume of time-sampled data.

14. The process of claim 1, wherein the converting step includes the step of coarse quantizing to increase contrast and reduce computational complexity of said time-sampled reflection values.

15. The process of claim 1, wherein the converting step includes the step of normalizing to maximize the dynamic range of said time-sampled reflection values.

16. An ultra wideband sensor device for extracting physiological data from a patient, said device comprising:

a pulse repetition frequency generator configured to generate a baseband pulse train;

a transmitter connected to a first antenna, the transmitter configured to generate a series of low voltage, short-duration pulses based on the baseband pulse train for transmission as an emitted signal from the first antenna as an ultra-wide band spectrum signal;

a delay range configured to output a delayed version of the baseband pulse train;

a receiver connected to a second antenna, the receiver triggered by the output of the delay range wherein the receiver is configured to process reflections of the emitted signal received by the second antenna;

a controller configured to emit a synchronization signal; and

a signal processor including an extractor, wherein the signal process is configured to process information from the receiver and to generate a first matrix of time-sampled reflection values at various depths and sample intervals of the synchronization signal, and wherein the extractor is configured to optimize the information in the first matrix to derive a second matrix from which physiological data may be extracted,

wherein the controller synchronizes the activity of the transmitter and signal processor.

17. The device of claim 16, further comprising a user interface for displaying the extracted physiological data.

18. The device of claim 16 wherein the delay range is configured to operate in a range gate mode and a range finder mode.

19. The device of claim 16 wherein the extractor is configured to indicate a cardiopulmonary measurement.

20. The device of claim 16 wherein the signal processor comprises a focuser configured to modify the processing of information from the receiver based on information extracted from past time-sampled reflection data.

21. The device of claim 16 wherein the signal processor comprises a reducer configured to process the first matrix of time-sampled reflection data and output a modified matrix of time-sampled reflection data.

22. The device of claim 21 wherein the reducer is configured to subtract static reflections from the first matrix of time-sampled reflection data to generate the modified matrix of time-sampled reflection data.

23. The device of claim 21 wherein the reducer is configured to reduce the size of the first matrix of time-sampled reflection data in creating the modified matrix of time-sampled reflection data.

24. The device of claim 21 wherein the reducer is configured to normalize the values of the first matrix of time-sampled reflection data to generate the modified matrix of time-sampled reflection data.

25. The device of claim 16 wherein the signal processor comprises a transformer configured to transform the first matrix of time-sampled reflection data to the frequency domain.

26. The device of claim 16 wherein the signal processor comprises a transformer configured to transform the second matrix of time-sampled reflection values to the frequency domain.

27. The device of claim 16 wherein the signal processor comprises an estimator configured to estimate physiological parameter from the amplitudes of values from the second matrix of time-sampled reflection data.

28. The device of claim 16 wherein the signal processor comprises:

a modeler including a database of filters for matching against the reflection values in the second matrix; and

a correlator to calculate a matrix of correlation coefficients based on the correlation of the reflection values in the second matrix and one or more of the filters in the database.

29. The device of claim 16 wherein the signal processor comprises a selector configured to process a confidence value of the indicator of a physiological measurement of the patient.

30. The device of claim 16, further comprising an analyzer configured to detect deviation of the indicator of physiological measurement output by the signal processor from one or more expected ranges.

31. The device of claim 16 wherein the transmitter is immediately adjacent to the antenna and the receiver is immediately adjacent to either the antenna or a second antenna.

32. The device of claim 16 wherein the ultra wideband receiver comprises a second antenna.

33. A process employing ultra wideband radar return signals to extract physiological data from one or more bodily organs or physiological processes of a patient, said process comprising:

transmitting an emitted signal from an antenna as an ultra-wide band spectrum signal, wherein the emitted signal comprises a plurality of individual low voltage, short-duration pulses;

receiving a plurality of reflections for each individual low voltage, short-duration pulses of the emitted signal at a receiver, wherein each reflection corresponds to a depth into the patient'"'"'s body based on a fixed time-delay from the emitted signal;

processing the reflections received by the receiver to generate a first matrix of time-sampled reflection values at a plurality of depths for at least a subset of the plurality of individual low voltage, short-duration pulses;

converting the first matrix of time-sampled reflection values into a reduced matrix; and

extracting physiological data from the reduced matrix using frequency spectrum analysis and statistical filtering.

34. An ultra wideband sensor device for extracting physiological data from a patient, said device comprising:

a pulse repetition frequency generator configured to generate a baseband pulse train;

a transmitter connected to an antenna, the transmitter configured to generate a series of low voltage, short-duration pulses triggered by the baseband pulse train for transmission as an emitted signal from the antenna as an ultra-wide band spectrum signal;

a delay range configured to output a delayed version of the baseband pulse train;

an ultra wideband receiver, the receiver triggered by the output of the delay range to detect reflections of the emitted signal at different depths; and

a signal processor configured to process reflections of the emitted signal received by the receiver and to generate a first matrix of time-sampled reflection values at various depths and time intervals, wherein the signal processor includes an extractor that is configured to optimize the information in the first matrix to derive a second matrix from which physiological data may be extracted.

35. The device of claim 34, further comprising a controller configured to emit a synchronization signal to synchronize the operation of the transmitter and signal processor.

36. The device of claim 34, further comprising a user interface for displaying the extracted physiological data.

37. The device of claim 34 wherein the delay range is configured to operate in a range gate mode and a range finder mode.

38. The device of claim 34 wherein the extractor is configured to indicate a cardiopulmonary measurement.

39. The device of claim 34 wherein the signal processor comprises a focuser configured to modify the first matrix of time-sampled reflection values based on information extracted from past time-sampled reflection data.

40. The device of claim 34 wherein the signal processor comprises a reducer configured to process the first matrix of time-sampled reflection values and output a modified matrix of time-sampled reflection data.

41. The device of claim 40 wherein the reducer is configured to subtract static reflections from the first matrix of time-sampled reflection values to generate the modified matrix of time-sampled reflection data.

42. The device of claim 40 wherein the reducer is configured to reduce the size of the matrix of time-sampled reflection values in creating the modified matrix of time-sampled reflection data.

43. The device of claim 40 wherein the reducer is configured to normalize the values in the matrix of time-sampled reflection values to generate the modified matrix of time-sampled reflection data.

44. The device of claim 40, wherein the ultra wideband receiver comprises a second antenna.

45. The device of claim 34 wherein the signal processor comprises a transformer configured to transform the first matrix of time-sampled reflection values to the frequency domain.

46. The device of claim 34 wherein the signal processor comprises a transformer configured to transform the second matrix of time-sampled reflection values to the frequency domain.

47. The device of claim 34 wherein the signal processor comprises an estimator configured to estimate physiological parameter from the amplitudes of values from the second matrix of time-sampled reflection data.

48. The device of claim 34 wherein the signal processor comprises:

a modeler including a database of filters for matching against the reflection values in the second matrix; and

a correlator to calculate a matrix of correlation coefficients based on the correlation of the reflection values in the second matrix and one or more of the filters in the database.

49. The device of claim 34 wherein the signal processor comprises a selector configured to process a confidence value of the indicator of a physiological measurement of the patient.

50. The device of claim 34, further comprising an analyzer configured to detect deviation of the indicator of physiological measurement output by the signal processor from one or more expected ranges.

51. The device of claim 34, wherein the transmitter is immediately adjacent to the antenna.