Systems and methods for detecting physical changes without physical contact
Inventors
LANGLEY, II, John B. • McIlroy, Guy
Assignees
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Publication Number
US-11253163-B2
Publication Date
2022-02-22
Expiration Date
Abstract
Systems and methods are provided for detecting and analyzing changes in a body. A system includes an electric field generator, an external sensor device, a quadrature demodulator, and a controller. The electric field generator is configured to generate an electric field that associates with a body. The external sensor device sends information to the electric field generator and is configured to detect a physical change in the body in the electric field, where the physical change causes a frequency change of the electric field. The quadrature demodulator receives the electric field from the electric field generator and is configured to detect the frequency change of the electric field and to produce a detected response. The controller, coupled to the electric field generator, is configured to output a frequency control signal to the electric field generator and to modify the frequency of the electric field by adjusting the frequency control signal.
Core Innovation
The invention provides a non-contact monitoring system for detecting and analyzing a change in a body using an electric field generator that generates an electric field associated with the body. An external sensor device sends information to the electric field generator and is configured to detect a physical change in the body in the electric field, where the physical change causes a frequency change of the electric field. The system detects the frequency change using a quadrature demodulator and produces a detected response.
A controller receives the detected response and outputs a frequency control signal to the electric field generator to modify the frequency of the electric field. The detected response is processed to include at least a frequency component, and the control modifies the electric-field frequency associated with the body. The description further includes separating the demodulator output into low frequency component and high frequency component for processing.
To handle dissipation and amplitude effects, the described system includes an amplitude reference source and an amplitude comparison switch that generates an amplitude comparison signal. A signal processor analyzes filtered response and the amplitude comparison signal to extract bodily functions and other material or physiological metrics. The system also includes tuning by adjusting the electric-field generator’s oscillator frequency to expand the quadrature demodulator’s linear frequency range without loss of sensitivity, supported by examples of resonant circuit implementations and linearity regions.
Claims Coverage
The document includes three independent claims: a system claim, a method claim, and a non-transitory computer readable medium claim. Across these claims, the core inventive features center on electric-field-associated frequency-shift detection via a quadrature demodulator and controller-based frequency control, with additional dependent coverage for linear frequency range and amplitude comparison.
Electric field generator associates with the body
An electric field generator configured to generate an electric field that associates with the body.
External sensor device detects physical change causing frequency change
An external sensor device that sends information to the electric field generator, configured to detect a physical change in the body in the electric field, wherein the physical change causes a frequency change of the electric field.
Quadrature demodulator detects frequency change and produces detected response
A quadrature demodulator that receives the electric field from the electric field generator, configured to detect the frequency change of the electric field generated by the electric field generator and to produce a detected response.
Controller outputs frequency control signal to modify electric field frequency
A controller, coupled to the electric field generator, configured to receive the detected response, output a frequency control signal to the electric field generator and to modify the frequency of the electric field.
Modified electric field frequency limited to quadrature demodulator linear frequency range
The modified frequency of the electric field lies within a specified linear frequency range of the quadrature demodulator.
Feedback-based frequency control using filtered low-frequency response
The controller adjusts a frequency control signal using a feedback response.
Feedback response defined as filtered output from a low pass filter
The feedback response is the filtered output from a low pass filter.
Inductor-capacitor tank oscillator implementation for the electric field generator
The oscillator is an inductor-capacitor tank oscillator.
Amplitude reference comparison path analyzed by signal processor
A system further includes an amplitude reference source and an amplitude comparison switch that compares the amplitude reference to the amplitude of an electric field generator to produce an amplitude comparison, which the signal processor receives and analyzes.
Overall claim coverage centers on generating an electric field associated with the body, detecting a physical change that causes a frequency change, using a quadrature demodulator to produce a detected response with at least a frequency component, and using a controller to output a frequency control signal that modifies the electric-field frequency. Dependent coverage further specifies operating constraints tied to the quadrature demodulator linear frequency range, feedback response defined by low-pass filtering, oscillator implementation, and an amplitude reference/comparison signal path analyzed by a signal processor.
Stated Advantages
Expands the quadrature demodulator’s linear frequency range without loss of sensitivity.
Documented Applications
Detecting and analyzing bodily functions including respiration and heart rate/pulse.
Determining other material or physiological metrics including blood pressure and infant life signs.
Driver drowsiness/safety monitoring using the system.
Sensor fusion for combining signals.
Material/food/fluid/void detection.
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