Heart Sound Extraction via Piezoelectric Sheet Sensor
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Solution Overview
Problem
Current methods for detecting extra heart sounds (sounds III and IV) are cumbersome and require advanced auscultation skills or the use of electronic stethoscopes, making daily monitoring of outpatients challenging and inefficient.
Innovation Solution
A heart sound extraction device that acquires piezoelectric signals from a sheet sensor, extracts heart sound signals, and sets specific time windows for analysis based on respiratory and heart sound characteristics, allowing for the identification of extra heart sounds without direct contact sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a body motion sensor is used to monitor heart sounds remotely, then patient burden is reduced and daily monitoring becomes easier, but the heart sound signal becomes much weaker and is easily affected by noise
Solution Approach 1:
The patent extracts the heart sound signal from the noisy body motion sensor output by identifying specific time windows where heart sounds occur. The extraction unit isolates the heart sound component from the composite signal containing body motion, respiratory effort, and pulse signals, enabling reliable detection despite the noisy environment.
Solution Approach 2:
The patent performs preliminary identification of time windows containing heart sounds before detailed analysis. By detecting candidate time windows based on signal characteristics and then confirming heart sounds within these windows, the system prepares the data in advance for accurate extra heart sound detection.
2Reliability
If an electronic stethoscope or high-performance microphone is used to collect phonocardiogram, then heart sound signal quality is improved, but patient burden increases and daily monitoring becomes difficult
Solution Approach 1:
The patent uses a body motion sensor that can be easily placed on the patient's body to capture vibrations, creating a copy of the heart sound signal without requiring direct contact with the heart surface. This indirect measurement approach maintains sufficient signal quality while dramatically improving ease of use and enabling remote monitoring.
3Measurement precision
If advanced auscultation skills are required to determine extra heart sounds, then detection accuracy is improved, but the complexity of the monitoring process increases and requires specialized medical personnel
Solution Approach 1:
The patent implements automatic detection algorithms that perform the complex analysis of extra heart sounds without requiring manual auscultation skills. The system self-identifies time windows containing heart sounds, extracts the signals, and detects extra heart sounds automatically, replacing the need for specialized medical personnel while maintaining high detection accuracy.
Solution Approach 2:
The patent replaces the mechanical process of manual auscultation by trained physicians with an automated electronic detection system. The system uses signal processing algorithms to identify and analyze heart sounds, substituting human expertise with computational methods that achieve comparable or superior accuracy without requiring specialized skills.
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
Enables the accurate extraction and analysis of heart sound signals from noisy sensor outputs, facilitating the detection of extra heart sounds and reducing the burden on patients and medical staff, thereby supporting early disease detection and treatment.
Implementation Method 1
a sheet sensor that outputs a piezoelectric signal depending on the vibration applied
Data Source
AI summary
A heart sound extraction device 3 comprises an acquisition unit 31 that, while a subject is lying on a sheet sensor that outputs a piezoelectric signal depending on the vibration applied, continuously acquires the piezoelectric signal output from the sheet sensor; a heart sound signal extraction unit 32c that extracts the heart sound signal of the subject from the piezoelectric signal; and a time window setting unit 32g that sets at least any of the following time windows in the extracted heart sound signal: (1) a time window in which the reciprocal of the standard deviation of respiratory frequency is maximum or equal to or greater than a predetermined value, (2) a time window in which the periodic respiratory power is maximum or equal to or greater than a predetermined value, (3) a time window in which the amplitude of the heart sound signal is maximum or equal to or greater than a predetermined value, (4) a time window in which the amplitude variation of the heart sound signal is minimum or equal to or less than a predetermined value, (5) a time window including the time zone of apnea in time window (2), (6) a time window in which the standard deviation of the heartbeat amplitude is minimum or equal to or less than a predetermined value, and (7) a time window in which the standard deviation of heartbeat intervals is minimum or equal to or less than a predetermined value.