MICRO POWERED ULTRA-HIGH RESOLUTION ELECTROMAGNETIC SENSOR WITH REAL TIME ANALOG CIRCUITRY BASED ARTIFACT CANCELLATION

• US 20180059059A1
• Filed: 08/27/2017
• Published: 03/01/2018
• Est. Priority Date: 08/28/2016
• Status: Active Grant

• Current Assignee: Xtrava, Inc.
• Original Assignee: Xtrava, Inc.
• Inventors: Sarhan, Sameh, Zuckerman, Lawrence Herbert
• Granted Patent: US 10,641,734 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 2562/0223 Magnetic field sensors
• 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 5/242 Detecting biomagnetic fields, e.g. magnetic fields produced by bioelectric currents
• CPC Class Codes: A61B 5/6804 Garments; Clothes
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: G01N 27/72 by investigating magnetic variables

Abstract

An ultra-miniature and micro-powered system, apparatus, and method utilizing electromagnetic imaging via minute eddy currents, analog circuit averaging and artifact cancellation, that attaches to the outside of clothing and measures internal bodily functions including but not limited to heart rate, respiration rate, and wetness of underclothing

Claims

1. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry using the same or auxiliary sensors to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body.

2. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry using the same or auxiliary sensors to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body,

where the signal containing the unwanted artifact may be separately filtered to obtain its spectral components to the exclusion of all other signals.

3. A method comprising each and every element shown and described above.

4. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital circuitry to concentrate on small ranges of the measured variable that contain desired information about the human body and disregard the vast remaining portions of the total range

5. A method comprising each and every element shown and described above.

6. An electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry using the same or auxiliary sensors to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body,

accomplishes cancellation of artifact signal from relative motion of said instrument and subject human body, by employing two eddy current loss measurement modules feeding a difference measuring circuit, one with a probe that produces magnetic flux within the target tissues and one with a smaller probe that produces magnetic flux only as far as the outer body layers.

7. An electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body,

accomplishes cancellation of artifact signal from relative motion of said instrument and subject human body, by employing a single eddy current loss measurement module that includes sample and hold circuits and a difference measuring circuit to capture eddy current loss readings at two frequencies at alternating time intervals, where the higher frequency reading produces magnetic flux within the target tissues and where the lower frequency reading produces magnetic flux only as far as the outer body layers.

8. An electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body,

accomplishes cancellation of artifact signal from relative motion of said instrument and subject human body, by employing a single eddy current loss measurement module that includes sample and hold circuits and a difference measuring circuit to capture eddy current loss readings at two tank circuit power levels at alternating time intervals, where the higher power level reading produces magnetic flux within the target tissues and where the lower power level reading produces magnetic flux only as far as the outer body layers.

9. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital cancellation circuitry using auxiliary sensors to separate desired measured values such as motion of internal organs and fluids, from undesired artifact signals such as those from relative motion of said instrument and subject human body.

accomplishes cancellation of artifact signal from relative motion of said instrument and subject human body, by employing an eddy current loss measurement module feeding a difference measuring circuit, along with an accelerometer and two cascaded time integrator circuits.

10. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital circuitry to concentrate on small ranges of the measured variable that contain desired information about the human body and disregard the vast remaining portions of the total range,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level for sufficiently slow changes of probe eddy current loss,

where changes of probe eddy current loss that are rapid compared with said controller time constant register as oscillator output level changes instead of said feedback circuit gain control signal

11. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital circuitry to concentrate on small ranges of the measured variable that contain desired information about the human body and disregard the vast remaining portions of the total range,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level for sufficiently slow changes of probe eddy current loss,

where changes of probe eddy current loss that are rapid compared with said controller time constant register as oscillator output level changes instead of said feedback circuit gain control signal

where, during closed control loop operation, oscillator output is maintained at a higher level than that necessary to sustain oscillation;

so that the open control loop scale present at the Open Loop Output is expanded for increased eddy current loss amounts.

12. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital circuitry to concentrate on small ranges of the measured variable that contain desired information about the human body and disregard the vast remaining portions of the total range,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level,

where changes of probe eddy current loss register at said feedback circuit gain control signal,

where a sample and hold circuit is switched from sample to hold in order to switch registration of probe eddy current loss from feedback circuit gain control signal to oscillator output level signal.

13. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

employs analog or digital circuitry to concentrate on small ranges of the measured variable that contain desired information about the human body and disregard the vast remaining portions of the total range,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level,

where changes of probe eddy current loss register at said feedback circuit gain control signal,

where a sample and hold circuit is switched from sample to hold in order to switch registration of probe eddy current loss from feedback circuit gain control signal to oscillator output level signal.

where, during closed control loop operation, in Sample mode, oscillator output is maintained at a higher level than that necessary to sustain oscillation;

so that in Hold mode, the open control loop scale present at the Open Loop Output is expanded for increased eddy current loss amounts.

14. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level for sufficiently slow changes of probe eddy current loss,

where changes of probe eddy current loss that are rapid compared with said controller time constant register as oscillator output level changes instead of said feedback circuit gain control signal,

Where an isolated artifact signal from any type of artifact and from any type of sensor are delivered as an auxiliary current source to said tank circuit in order to cancel said artifact.

15. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level for sufficiently slow changes of probe eddy current loss,

where changes of probe eddy current loss that are rapid compared with said controller time constant register as oscillator output level changes instead of said feedback circuit gain control signal,

Where an isolated artifact signal from any type of artifact and from any type of sensor are delivered as an auxiliary current source to said tank circuit in order to cancel said artifact.

where, oscillator output is maintained by the control loop at a higher level than that necessary to sustain oscillation;

so that for both closed and open control loop operating modes, the transfer curves for signals entering said auxilliary current source will have increased linearity and/or expanded scale for increased eddy current loss amounts.

16. A system comprising an electromagnetic imaging instrument utilizing minute eddy current sensing techniques suitable for safe application within the human body that mounts on outer or inner clothing,

includes an eddy current probe parallel tuned circuit that is the tank circuit of an oscillator whose feedback circuit gain is set by a controller to create a constant oscillator output level for sufficiently slow changes of probe eddy current loss,

where changes of probe eddy current loss that are rapid compared with said controller time constant register as oscillator output level changes instead of said feedback circuit gain control signal,

where multiple isolated artifact signals from any types of artifacts and from any types of sensor are delivered as auxiliary current sources to said tank circuit in order to cancel said artifacts.