Bioelectrical Impedance Measurement Mode Switching
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Solution Overview
Problem
Existing bioelectrical impedance measurement methods require significant time to stabilize contact impedance, leading to prolonged measurement times and reduced accuracy due to the need for separate stabilization times in four-point and two-point measurement modes.
Innovation Solution
The apparatus switches between four-point and two-point measurement modes by short-circuiting or opening electrodes based on impedance thresholds and time elapsed, using the first and second impedances measured before and after mode switches to calculate bioelectrical impedance in real-time, eliminating the need for stabilization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If four-point measurement mode is used to improve measurement accuracy, then measurement precision is improved, but measurement time increases due to required stabilization period
Solution Approach 1:
The patent implements periodic switching between four-point and two-point measurement modes. The system alternates between these modes in a predetermined sequence, performing multiple four-point measurements separated by two-point measurements. This periodic action allows the system to maintain high measurement accuracy through four-point mode while using two-point mode to reset and reduce contact impedance stabilization time, thereby reducing overall measurement time.
2Reliability
If separate stabilization times are allocated for four-point and two-point measurement modes, then measurement reliability is improved, but productivity decreases
Solution Approach 1:
The patent employs dynamic measurement mode switching where the system transitions between four-point and two-point modes based on predetermined sequences and contact impedance feedback. This dynamic approach allows the system to adaptively allocate stabilization time only when necessary (during mode transitions), rather than requiring separate fixed stabilization periods for each mode. The dynamic switching maintains measurement reliability while significantly improving measurement speed and productivity.
3Speed
If measurement mode switching is implemented to reduce stabilization time, then measurement speed is improved, but device complexity increases
Solution Approach 1:
The patent combines four-point and two-point measurement circuits into a single integrated measurement system. The switching mechanism merges the functionality of both measurement modes into one unified apparatus, sharing common components such as the voltage meter, current source, and processor. This merging approach enables mode switching to reduce stabilization time and improve measurement speed while minimizing the increase in device complexity through component sharing and integration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for faster and more accurate bioelectrical impedance measurements by estimating changing contact impedance in real-time, reducing overall measurement time while maintaining high accuracy.
Implementation Method 1
apparatus for measuring bioelectrical impedance... a current source configured to apply a constant current to an object through a first electrode and a second electrode; a voltmeter configured to obtain a voltage applied to a third electrode and a fourth electrode due to the constant current
Data Source
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AI summary
An apparatus for measuring bioelectrical impedance includes a current source configured to apply a constant current to an object through a first electrode and a second electrode; a measurement mode switcher configured to switch a measurement mode from a first measurement mode to a second measurement mode in response to a measurement mode switch signal; a voltmeter configured to obtain a voltage applied to a third electrode and a fourth electrode due to the constant current applied to the object; and a processor configured to obtain first impedance based on a first voltage obtained by the voltmeter immediately before start of a measurement mode switch, obtain second impedance based on a second voltage obtained by the voltmeter immediately after completion of the measurement mode switch, and obtain bioelectrical impedance of the object based on the first impedance and the second impedance.