Non-Contact Heart Rate Measurement Using BCG Signal Filtering
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Solution Overview
Problem
Non-contact sensors used for heart rate measurement, such as PVDF sensors, face challenges in accurately measuring heart rate due to noise from external environments, affecting the reliability of inter-beat interval estimation.
Innovation Solution
An apparatus and method that estimate the inter-beat interval of a ballistocardiograph (BCG) signal using a non-contact sensor, involving a signal meter, an inter-beat interval estimator, and filters to determine confidence values and repetition degrees, filtering out noise by comparing these values with threshold values to produce accurate heart rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a non-contact sensor is used to measure heart rate, then the convenience and comfort for the user is improved, but the measurement accuracy deteriorates due to noise from external environments
Solution Approach 1:
The patent divides the heart rate measurement process into multiple independent stages: signal acquisition, inter-beat interval estimation, confidence value filtering, and repetition degree filtering. Each stage processes specific aspects of the signal separately, allowing noise reduction without compromising the overall measurement convenience provided by non-contact sensing.
Solution Approach 2:
The patent introduces intermediate processing parameters (confidence values and repetition degrees) that act as mediators between the raw noisy signal and the final heart rate measurement. These intermediaries filter out noise influence while preserving the essential cardiac information, enabling accurate measurement despite environmental interference.
2Measurement precision
If filtering and correction processes are applied to inter-beat intervals, then the measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent implements self-service filtering where the system uses its own estimated inter-beat intervals to generate confidence values and repetition degrees, which then automatically filter the intervals. This self-referential approach improves accuracy without requiring external complex filtering mechanisms, keeping the device complexity manageable.
Solution Approach 2:
The patent transforms the raw inter-beat interval data into new parameter spaces (confidence values and repetition degrees) before final measurement. By changing parameters rather than directly filtering the original signal, the system achieves higher accuracy through mathematical transformation rather than complex physical filtering hardware.
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 solution enhances heart rate measurement accuracy and convenience by filtering and correcting noise in inter-beat intervals, providing reliable results under various environments using a non-contact sensor.
Implementation Method 1
a method of measuring a heart rate using a non-contact sensor such as a polyvinylidene fluoride (PVDF) sensor
Data Source
AI summary
The present disclosure relates to a technique for estimating the inter-beat interval (IBI) of a ballistocardiograph (BCG) signal measured using a non-contact sensor, filtering and correcting inaccurate information in the inter-beat interval estimated through clustering, and outputting a heart rate measurement result based on the filtered and corrected inter-beat interval. According to one embodiment of the present disclosure, an apparatus for measuring a heart rate may include a signal meter for measuring a ballistocardiograph (BCG) signal from a heart rate measurement target; an inter-beat interval estimator for estimating an inter-beat interval (IBI) by applying a window to the measured BCG signal; a first filter for determining a confidence value for the probability values of the estimated inter-beat interval, filtering the estimated inter-beat interval by comparing the determined confidence value with a first threshold value, and determining a first estimated value; a second filter for determining a repetition degree indicating that identical beat values are successively estimated for the estimated inter-beat interval, filtering the estimated inter-beat interval by comparing the determined repetition degree with a second threshold value, and determining a second estimated value; and a heart rate output device for determining a third estimated value for the estimated inter-beat interval based on the determined first and second estimated values and outputting a heart rate based on the determined third estimated value.