Calibrating Diagnostic Devices Using Resting Signal Vectors
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Solution Overview
Problem
Diagnostic measuring devices for biological signals face challenges in defining a reliable and biologically meaningful zero point, especially in cardiography, due to variability in heart muscle activity and interference from offset voltages.
Innovation Solution
A method is developed to identify a quiet segment in the signal where the vector changes minimally, determining a mean vector within this segment as the reference vector for calibration, which can be applied to various biological signals represented as n-dimensional vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zero point is defined based on physiological justification, then the biological meaningfulness is improved, but the reliability of determination deteriorates due to variability in heart muscle activity
Solution Approach 1:
The patent introduces an intermediary computational process that analyzes the temporal behavior of measured values to identify a rest section. Instead of directly defining the zero point from raw physiological data, the system uses an intermediate step of detecting periods with minimal vector change, thereby mediating between the raw variable physiological signals and the required stable reference point.
Solution Approach 2:
The patent applies preliminary action by first identifying a rest section in the signal before establishing the zero point. The system performs preliminary analysis to detect time periods where the vector magnitude changes minimally, and only after this preliminary detection does it proceed to calculate the mean vector as the zero point reference.
2Measurement precision
If offset voltages are filtered out to improve measurement accuracy, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the offset voltage component from the measured signal by identifying and analyzing only the rest section where physiological activity is minimal. Instead of applying complex filtering across the entire signal, the system extracts the reference period and calculates the mean vector solely from this extracted portion, thereby removing offset voltages with minimal processing complexity.
3Measurement precision
If individual calibration is performed for each measurement to improve precision, then the measurement precision is improved, but the time required for calibration increases
Solution Approach 1:
The patent implements self-service calibration by enabling the measuring device to automatically identify its own rest section and calculate its own zero point reference without external intervention. The system autonomously detects periods of minimal vector change and computes the mean vector, allowing individual calibration to be performed automatically and efficiently.
Data Source
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AI summary
The invention relates to a method for calibrating a diagnostic measuring device for biological signals, which can be represented as vectors, such as the representation of cardiac potentials in cardiography. The method determines a zero-point vector or reference point for the calibration of the measuring device as an average vector within a resting section having minimal change of the signal. A search range for such a resting section can be limited to a time frame within the entire measuring period and biologically justified, for example, by means of empirical data that indicate physiological resting phases and/or from the knowledge of the course of the physiological process to be examined.