• Journal of Biomedical Engineering Research
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• v.22 no.1
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• pp.9-17
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• 2001

의료영상 처리는 의료 전문가들이 의료영상을 이용한 진단, 치료, 및 연구를 함에 있어 중요한 역할을 하고 있다. 많은 영상 분할 방법들이 의료영상 처리분야에서 성공적으로 사용되고 있다. 본 논문에서는 CT 영상에서 간 영역을 자동으로 추출하는 방법을 제시한다. 본 논문에서는 간 영역을 추출하기 위해 co-occurrence matrix를 적용하였고, 추출된 영역에서 뼈와 근육, 신장 영역을 제거하였다. 제안된 방법은 의료 전문가가 추출한 결과와 비교하여 좋은 결과를 보여주었다.

• Journal of Biomedical Engineering Research
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• v.21 no.5
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• pp.457-467
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• 2000

In this paper, we propose the method to extract the anatomical objects in medical images using active contour models and genetic algorithms. The performance of active contour models is mostly decided by the optimization of active contour model's energy. So, we propose to use genetic algorithms to optimize the energy of active contour models. We experimented our proposed method on the femoral head medical images and proved that our method provides very acceptable results from any initialization of active contour models.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.555-560
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• 1999

간질은 신경세포의 일부가 짧은 시간동안 과도한 전기를 발생시킴으로써 일어나는 신경계의 발작적 증상으로 배경 활동파와는 구별되는 극파, 예파, 예파와 서파를 동반한 극서파 복합(sharp and slow complexes)의 뇌파 특징파를 갖는다. 장시간의 뇌파기록에서 시간의 절약과, 정량화를 위해 컴퓨터를 이용한 간질 파형의 자동 검출은 객관성을 높이고 정량적인 해석을 위해 필수적이다. 본 연구에서는 간질 뇌파를 검출하기 위해 웨이브렛 변환과 신경망을 사용하였다. 웨이브렛 변환은 잡음을 제거하고 간질 뇌파의 특징을 강조하며 신경망의 입력노드수를 줄였다. 전문가에 의해서 분류된 간질특성과 정상뇌파를 신경망에 입력시켜 최적의 신경망구조를 선택하였고, 검출 문턱치를 설정하였다. 신경망은 200ms(26개의 데이터포인트)신호의 웨이브렛 결과와 웨이브렛 변환후 데이터 상의 최대, 최소 기울기가 입력되어 전체 28개의 입력 노드로 구성하였다. 은닉층은 18노드, 문턱치값은 민감도와 선택도가 일치하는 0.65가 사용되었다. 결과로 임상 환자 데이터에 입력되어 78.54% 의 검출률을 보였다.

• Journal of Biomedical Engineering Research
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• v.20 no.5
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• pp.529-536
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• 1999

임상적인 응용을 목적으로 하는 전산화 신경 심리 검사 시스템을 개발하였다. 개발된 시스템은 국소적 뇌기능 장애 진단에 뛰어난 14개의 검사록 구성되어 있으며 집중력·언어능력, 공간 및 도형 인지 능력, 기억력, 운동 집중 능력 등을 진단하게 된다. 개발된 시스템은 멀티미디어 객체지향개념에 의거하여 설계 구현되었고, 마이크로소프트 Windows 에 기반을 둔 그래픽 인터페이스를 채용하여 운용이 용이하도록 하였다. 또한 마우스와 터치스크린을 이용하여 피검사자로부터 입력을 손쉽게 받아들 일수 있도록 하였으며, 색체 단어검사, 범주화검사, 언어기억검사들을 한글화하여 검사의 효용성을 향상시켰다. 개발된 시스템을 정상인 그룹과 환자에 적용한 결과 뇌기능 장애 진단에 유용하게 사용될 수 있음을 확인할수 있었다.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.149-154
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• 1999

In anatomical aspects, magnetic resonance image offers more accurate information than other medical images such as X ray, ultrasonic and CT images. This paper introduces a method that segments and detects lesion for 2 dimensional axial MR brain images automatically. Image segmentation process consists of 2 stages. First stage extracts cerebrum region using thresholding and morphology. In the second stage, white matter, gray matter and cerebrospinal fluid in the cerebrum are extracted using FCM, We could improve processing time as removing uninterested region. Finally symmetry measure and anatomical Knowledge are used to detect lesion.

• Journal of Biomedical Engineering Research
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• v.16 no.3
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• pp.265-270
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• 1995

An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for chArging high voltage cApacitors, the weight and size of the magnetic net've stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec Experimental results of human nerve stimulations using the developed stimulator are presented.

• Proceedings of the KOSOMBE Conference
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• v.1985 no.06
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• pp.15-19
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• 1985

This study deals with a kind of signal processing, Kalman filtering techniques, which are applied to ultrasound signal to improve resolution capability. The main advantage of Kalman filter algorithm for the analysis of reflected ultrasound signal is its recursive structure which can be easily adapted to time-varing system. In state-space description of the system, the 6th order system produces the best spectral approximation to the source pulse. As a result of spectrum analysis, 6th order estimator for two closely spaced (0.5mm) reflectors enhance resolution by 4dB - 10dB. By using this result, the possibility to detect even minute tumor is found.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.265-266
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• 1998

This paper describes a depth extraction algorithm in the stereo endoscopic images using adaptive window. First, The relation between the 3D coordinates in the world and the 2D coordinates in the image plane is estimated using camera calibration. Next, stereo matching is performed to find the conjugate pairs in the left and right images. To improve the precision of the matching result, adaptive window which can be varied on the shape as well as on the size according to the area characteristics is used. Finally, the result from the stereo matching and that of camera modeling are combined to extract the real depth information.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.205-206
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• 1998

In this paper, we present the detection algorithm of interictal epileptic waveform using LVQ network and wavelet transform. First wavelet coefficients is used to represent the characteristics of a single channel EEG wave, and make a number of neural network input node smaller. Then, three-layer neural network employing LVQ network is trained and tested using parameters obtained from the first stage. This study showed that preprocessed EEG data can be successfully used to train ANNs to detect epileptogenic discharges with a high success.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.83-85
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• 1992

In this paper, the Infant Incubator Consisting of amp lifer, A/D Convert, I/O Expand, Watchdog Timer, Alarm Circuit. Display, and mirco-Computer part was developed. The care of Premature new borns of the required that they be in an environment in which temperature is elevaled and Controlled, because they are unable to regulated their own temperature. The central and processing methods based on micro-processor employ the flexibility, and economy over other conventional system. The system characteristic were as follows 1) system based on micro-processor. 2) Easy-to read, touch-Operate control panel all displays and indicators 3) System flexibility.