Micro powered ultra-high resolution electromagnetic sensor with real time analog circuitry based artifact cancellation
First Claim
Patent Images
1. An electromagnetic imaging instrument to measure internal properties and movement of a target object within a container or body, where there is also a spurious relative motion of the instrument and the container or body, the instrument comprising:
- an eddy current measuring apparatus that outputs a composite signal containing information about said internal properties and movement of the target object contaminated with information about the spurious relative motion;
an auxiliary motion sensing means driving an auxiliary motion sensing means processing circuitry having an auxiliary motion sensing means processing circuitry output signal that contains only information about the spurious relative motion; and
a difference measuring circuit to output a signal that subtracts a value of one signal from another, wherein, the composite signal is fed to a first input of the difference measuring circuit and the auxiliary motion sensing means processing circuitry output signal is fed to a second input of the difference measuring circuit, anda signal processing means, wherein the signal processing means output contains less contamination from information about the spurious relative motion than the composite signal.
0 Assignments
0 Petitions
Accused Products
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.
9 Citations
15 Claims
-
1. An electromagnetic imaging instrument to measure internal properties and movement of a target object within a container or body, where there is also a spurious relative motion of the instrument and the container or body, the instrument comprising:
-
an eddy current measuring apparatus that outputs a composite signal containing information about said internal properties and movement of the target object contaminated with information about the spurious relative motion; an auxiliary motion sensing means driving an auxiliary motion sensing means processing circuitry having an auxiliary motion sensing means processing circuitry output signal that contains only information about the spurious relative motion; and a difference measuring circuit to output a signal that subtracts a value of one signal from another, wherein, the composite signal is fed to a first input of the difference measuring circuit and the auxiliary motion sensing means processing circuitry output signal is fed to a second input of the difference measuring circuit, and a signal processing means, wherein the signal processing means output contains less contamination from information about the spurious relative motion than the composite signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An electromagnetic imaging eddy current instrument to measure internal properties and movement of a target object within a container or body, where there is also a spurious relative motion of the instrument and the container or body, the instrument comprising:
-
an oscillator whose tank circuit consists of a parallel tuned circuit that includes a coil inductor also functioning as an eddy current probe, where the parallel tuned circuit is connected to an input of a buffer amplifier, an output of a voltage-to-current converter, a fixed bias current source and an auxiliary variable bias current source driven by a sensor means that measures the spurious relative motion of the instrument and the container or body; where the buffer amplifier feeds a signal input of a gain-controlled amplifier, which in turn feeds an input of the voltage-to-current converter; where the parallel tuned circuit, the buffer amplifier, the gain-controlled amplifier, and the voltage-to-current converter constitute the oscillator, where the buffer amplifier also feeds an amplitude demodulator which in turn feeds a signal input of a servo integrator; where the servo amplifier, through a cascaded sample and hold circuit in the sample mode and a low pass filter complete a closed control loop by feeding a control input of the gain-controlled amplifier; whereby the closed control loop maintains the oscillator output and the amplitude demodulator output at a constant level over a wide range of losses reflected to the parallel tuned circuit by the target object and container or body, as corrected for the spurious relative motion of the instrument and the container or body by the auxiliary variable bias current source, causing the servo integrator output level to represent only the loss reflected to the parallel tuned circuit by the target object; and where a closed control loop mode output of the instrument is the servo integrator output. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
Specification