Bioimpedance Measuring Device With Motion Artifact Detection
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Solution Overview
Problem
Existing bioimpedance monitoring devices struggle with signal distortions due to body movements, leading to unreliable and raw data measurements, which require additional effort for evaluation and do not provide a comprehensive view of the user's physical state.
Innovation Solution
A bioimpedance measuring device with multiple electrode sets and a microcontroller for signal evaluation, including low-pass and high-pass filtering to separate respiration and blood pulse signals, and a motion sensor to detect and mitigate artifacts, along with adaptive filtering and threshold evaluation for improved accuracy and user-friendly data interpretation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simple bioimpedance measuring device is used, then the device complexity is low and ease of operation is high, but measurement precision deteriorates due to signal distortions from body movements
Solution Approach 1:
The patent divides the measuring device into multiple independent electrode sets (first set with feed and measuring electrodes, second set with different spatial arrangement) that can be evaluated separately. This segmentation allows comparison of signals from different measurement paths to identify and eliminate movement artifacts while maintaining relatively simple individual sensor designs.
Solution Approach 2:
The patent combines multiple electrode sets and evaluation methods (impedance measurement, acceleration sensing, signal filtering) into a single integrated system. The microcontroller coordinates all components to perform artifact detection and signal correction, achieving high measurement precision through combined functionality rather than separate devices.
2Measurement precision
If multiple electrode sets and artifact detection are implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The microcontroller serves multiple functions: it controls the current source, amplifies and filters bioimpedance signals from multiple electrode sets, processes acceleration sensor data, performs artifact detection through signal comparison, and generates final evaluated results. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The patent introduces an acceleration sensor as an intermediary element that detects body movements and provides artifact information to the evaluation system. This intermediary allows indirect detection of movement artifacts without requiring complex direct measurement of signal distortions, simplifying the overall artifact detection mechanism.
3Ease of operation
If raw data is provided to users, then measurement precision is maintained, but ease of operation deteriorates due to lack of automated evaluation
Solution Approach 1:
The evaluation system automatically performs artifact detection, signal correction, and physiological parameter extraction without requiring user intervention or specialist knowledge. The system serves itself by internally processing raw data through filtering algorithms and comparison methods, then presenting only the final evaluated results to the user, eliminating the need for users to manually analyze raw data.
4Measurement precision
If all measured signals are processed, then measurement precision is maximized, but energy consumption increases
Solution Approach 1:
The evaluation system applies different processing quality levels to different signals based on their reliability. High-quality signals from stable electrode contacts receive full processing with artifact detection and filtering, while signals showing clear artifacts or poor quality undergo simplified processing or are discarded. This local quality approach optimizes energy usage by avoiding unnecessary processing of low-quality data.
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
The method provides reliable, accurate, and comprehensive vital parameter measurements, enabling direct user feedback without specialist knowledge, with enhanced detection of artifacts and energy-efficient operation by discarding low-quality signals, and supporting long-term monitoring with improved signal quality and reduced user intervention.
Implementation Method 1
a first set of electrodes for contacting the skin of a user, which consists of a pair of feed electrodes for introducing a measuring current into the skin and a pair of measuring electrodes arranged spaced apart from one another between the feed electrodes for detecting the voltage across the skin
Implementation Method 2
a respiration signal is derived by low-pass filtering
Implementation Method 3
a blood pulse signal is derived by high-pass filtering
Implementation Method 4
the measuring device comprises an acceleration sensor, which can detect a movement of the wristband
Data Source
Figure 1~2
AI summary
The method involves detecting a bio-impedance signal using a set of electrodes (30), where a respiratory signal is derived from the bio-impedance signal by low pass filtering. A blood pulse signal is derived by high pass filtering, where the respiratory signal and the blood pulse signal are assigned to signal evaluation for determining the derived parameters. The derived parameters are evaluated in a micro controller (21), which determines a defined body condition from the totality of the derived parameters. Another set of electrodes (40) is provided for evaluation of the derived parameters. An independent claim is included for a bio-impedance measuring device.