• 전기학회논문지
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• 제56권6호
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• pp.1139-1143
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• 2007

For the possible application of monitoring or diagnosing heart sounds in an ubiquitous healthcare environment. a small and light electro-stethoscope that can be attached in human body should be exploited. With this aim, this study proposes a new style of electro-stethoscope device that is composed of four hardware modules in wearable style. For this ambulatory heart sound collecting device, the several tests must be performed to check portability and material capability for collecting heart sounds. It turned out to be that the multi-channel electro-stethoscope can detect heart sound signals well even if it is not pinpointed in the accurate stethoscope point on a heart. Consequently, our ambulatory electro-stethoscope hardware system can be applied to monitor or diagnose abnormal heart sounds in the ubiquitous healthcare system.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권5호
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• pp.241-246
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• 2001

The conventional stethoscope can not store its stethoscopic sounds. Therefor a doctor diagnoses a patient with instantaneous stethoscopic sounds at that time, and he can not remember the state of the patient's stethoscopic sounds on the next. This prevent accurate and objective diagnosis. If the electronic stethoscope, which can store the stethoscopic sound, is developed, the auscultation will be greatly improved. This study describes an amplifier for electronic stethoscope system that can extract heart sounds of fetus as well as adult and alow us hear and record the sounds. Using the developed stethoscopic amplifier, clean heart sounds of fetus and adult can be heard in noisy environment, such as a consultation room of a university hospital, a laboratory of a university. Surprisingly, the heart sound of a 22-week fetus was heard through the developed electronic stethoscope. Pitch detection experiments using the detected heart sounds showed that the signal represents distinct periodicity. It can be expected that the developed electronic stethoscope can substitute for conventional stethoscopes and if proper analysis method for the stethoscopic signal is developed, a good electronic stethoscope system can be produced.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.107.3-107
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• 2001

This paper is concerned with the development of a simple digital stethoscope system for diagnosis of cardiac disorders. This system consists of an electronic stethoscope, IC sound recorder and a notebook computer. The cardiac sound is easily acquired by the electronic stethoscope and then recorded in IC memory stick so that the digital cardiac signal can be simply transmitted to the computer for signal display, disease diagnosis, and personal history record. A software is built with functions displaying the sound graphically and replaying the sound clearly. Further, a neural network recognition system for automatic diagnosis of cardiac disorders is also added to the software.

• 대한의용생체공학회:의공학회지
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• 제34권4호
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• pp.204-211
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• 2013

In this paper, an algorithm for suppressing acoustic noises contained in stethoscope sound is proposed and implemented in real-time using an embedded DSP system. Sound collected by stethoscope is down-sampled and band-pass filtered, and later an NLMS adaptive filter is used to cancel the acoustic noise induced from external noise sources. Also, the unpredictable impulsive noises due to fabric friction and instantaneous tapping are detected using the SD-ROM algorithm, and suppressed using an algorithm approximating the morphology filter. The proposed algorithm was tested using signals collected with a digital stethoscope mockup, and implemented on an ARM920T-based DSP system.

• 전기학회논문지
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• 제66권4호
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• pp.715-720
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• 2017

This study tries to analyze morphology and formant frequencies of linear prediction spectra of stethoscope sounds for heart diseased children. For this object, heart diseased stethoscope sounds were collected in the pediatrics of an university hospital. The collected signals were preprocessed and analyzed by the Burg algorithm, a kind of linear prediction analysis. The linear prediction spectra and the formant frequencies of the spectra for the stethoscope sounds for the normal and the diseased children are estimated and compared. The spectra showed outstanding differences in morphology and formant frequencies between the normal and the diseased children. Normal children showed relatively low frequency of F1(the first formant) and small negative slope from F1. VSD children revealed stiff slope change around F1 to F3. Spectra of ASD children is similar with the normal case, but have negative values of F3. F1-F2 difference of the functional murmur children were relatively large.

• 대한한방내과학회지
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• 제35권4호
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• pp.439-447
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• 2014

Objectives: The aim of this study was to investigate whether 1) variation of bowel sounds recorded stably through an electronic stethoscope in a sound insulation box can be related with that of gastric contraction and 2) if they are thus useful tool in the measurement of the gastric contractility in awake rats or not. Methods: Electrical potentials of both electronic stethoscope of bowel sound and force transducer were recorded simultaneously and continuously in the sound insulation box for the starting 30 min of basal state, and then 30 min of 0.2 ml normal saline administration, finally 30 min of 0.2 ml mosapride citrate solution (100 mg/Kg) in rats. Each motility index of normal saline or mosapride citrate treatment was presented with ratio against the basal state by using integrated electrical potentials. Results: A pattern of significance of gastric contractility between bowel sound and force transducer was showed analogously. Conclusions: The amplitude of bowel sounds recorded by the electronic stethoscope related with the intensity of gastric contractions. This confirms that a sound insulation box and electronic stethoscope are useful tools in the measurement of the gastric contractility of awake rats.

• 센서학회지
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• 제30권1호
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• pp.47-50
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• 2021

Human hearing sensitivity is frequency-dependent. The sensitivity is low at both ends of the audible frequency, and the sensitivity is the highest in the middle band at 3000 Hz. The heart sound of a healthy person is concentrated at a low frequency of 200 Hz or less, and despite using a stethoscope, the hearing sensitivity of the human body is low, and the stethoscope sound is low. Amplifying the sound of the stethoscope is not effective in distinguishing heart sounds in noisy environments because it maintains the same signal-to-noise ratio. In this study, a method of enhancing auditory stimulation was developed by applying a method of moving the spectrum of auscultation sounds into a high-frequency region where the human body is highly sensitive to hearing. The spectrum of the auscultation sound was moved up by 500 Hz in the frequency domain, and an inverse fast Fourier transform (FFT) was performed to reconstruct the auscultation sound. The heart sounds reconstructed by moving the spectra were divided into the first heart and second heart sound components, as in the original heart sound, and it was confirmed that the intensity was large in the cochleagram representing auditory stimulation. Therefore, this study suggested that spectral shift is a method to enhance auditory stimulation during auscultation without increasing the intensity of the auscultation sound.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.101-102
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• 2007

Heart diseases are critical and should be detected as soon as possible. A stethoscope is a simple device to find cardiac disorder but requires keen experiences in heart sounds. We evaluate a cardiac disorder classifier by using heart sounds recorded by a digital wireless stethoscope developed in this work. The classifier uses hidden Markov models with circular state transition to model the heart sounds. We train the classifier using two kinds of data: One recorded by using our stethoscope and the other sampled from a clean heart sound database. In classification experiments using 165 sound clips, the classifier shows the classification accuracy of 82% in classifying 6 cardiac disorder categories.

• 전기학회논문지
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• 제62권10호
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• pp.1444-1450
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• 2013

Esophageal stethoscope is used for monitoring the heart sounds and breath sounds of patients during surgery under a general anesthesia. Recently, an electronic esophageal stethoscope (EES)[1] has been developed for the purpose of real-time monitoring these information visually. This system uses only a microphone as the sound sensor. A drawback of the EES system is that it may be difficult to distinguish the first sound ($S_1$) and the second sound ($S_2$) of heart, because their periods are irregular depending on patients. In this paper, we propose an improved EES system in which the infrasound is measured by adding a pressure sensor as well as a sound sensor. We investigate some correlations between the infrasound and characteristics of the heart sound. The proposed system has been tested on 15 patients. The results show that the new system is capable of detecting the first sound more reliably and easily determining the heart rate and breathing period.

• 한국정보전자통신기술학회논문지
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• 제2권3호
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• pp.9-15
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• 2009

분만시 국내에서 영아 사망률은 약 1%에 이르고, 태아의 질병 발생과 사망은 계속적으로 일어나고 있으므로 저가의 태아 모니터링기술의 개발이 절실하다. 이를 위하여 본 연구에서는 임산부의 복부로부터 태아의 움직임과 심음을 검출할 수 있는 증폭기를 설계하여 고성능 태아 포노그램용 전자청진장치를 개발하고자 한다. 장치로부터 검출된 태아의 청진 신호는 듣거나 녹음할 수 있으며, PC에서 태아의 심음을 분석할 수도 있다. 개발된 증폭기를 이용하여 잡음에 노출된 일반 대학병원 환경에서 30명의 임산부를 대상으로 임상실험을 수행한 결과, 개발된 증폭기는 저잡음, 고이득의 특성을 나타내고, 임산부 중에서 빠른 경우 22주에서도 태아의 심음을 검출할 수 있었고, 심음의 주기검출이 가능하였다.