• 한국콘텐츠학회논문지
• /
• 제5권6호
• /
• pp.138-145
• /
• 2005

본 연구에서는 실명(loss of eyesight)의 원인 질병중 하나인 녹내장의 진행과 진단 등의 의료 정보제공을 목적으로 양방향 곡선 전개 방식을 이용하여 망막 영상에서 시신경 원판(optic disk)의 경계를 검출하는 방법을 제안한다. 정확한 경계 검출의 위하여 텍스처 병합(texture synthesis)기반의 이미지 인페인팅 방법으로 시신경 원판 위를 지나는 혈관을 제거하고 전처리 과정에서 발생하는 잡음제거와 경계의 보존을 위해 비등방성 확산 필터링(anisotropic diffusion filtering)을 행한다. 혈관이 제거된 망막 영상에서 시신경 원판의 경계 검출은 양방향 곡선 방식으로 검출한다. 실험 결과에서, 제안한 알고리즘은 복잡한 망막영상에도 효율적으로 시신경 원판을 검출한다는 것을 보여준다.

• 융합신호처리학회논문지
• /
• 제8권4호
• /
• pp.249-254
• /
• 2007

본 논문은 실명(loss of eyesight)의 원인 중 하나인 녹내장의 진행과 진단 등의 의료 정보제공을 목적으로 양방향 곡선 전개 방식을 이용하여 망막 영상에서 시신경 원판(optic disk)의 경계를 검출하는 방법을 제안한다. 정확한 경계 검출을 위하여 PDE 기반의 Image inpainting 방법으로 시신경 원판 위를 지나는 혈관을 제거하고 전처리 과정에서 발생하는 잡음제거와 경계의 보존을 위해 비등방성 필터링(anisotropic filtering)을 행한다. 혈관이 제거된 망막 영상에서 시신경 원판의 경계 검출은 초기 곡선에 강인한 양방향 곡선 방식으로 검출한다. 실험결과, 제안한 방법이 전체영상의 블러링 현상뿐만 아니라 시신경 원판 경계의 블러링 현상을 줄일 수 있었고, 기존의 방법에 비하여 정확한 경계를 검출할 수 있었다.

• 대한의용생체공학회:의공학회지
• /
• 제16권2호
• /
• pp.121-128
• /
• 1995

Information about retinal blood vessels can be used in grading disease severity or as part of the process of automated diagnosis of diseases with ocular menifestations. In this paper, we address the problem of detecting retinal blood vessels and optic disk (papilla) in eye-fundus images. We introduce an algorithm for feature extraction based on Fuzzy Clustering algorithm (fuzzy c-means). A method of finding the optic disk (papilla) is proposed in the eye-fundus images. Additionally, the inrormations such as position and area of the optic disk are extracted. The results are compared to those obtained from other methods. The automatic detection of retinal blood vessels and optic disk in the eye-rundus images could help physicians in diagnosing ocular diseases.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.312-316
• /
• 2004

The paper presents a technique to identify the boundary of the optic disc in infant retinal digital images using an approach based on active contours (snakes). The technique can be used to be develop a automate system in order to help the ophthalmologist's diagnosis the retinopathy of prematurity (ROP) disease which may occurred on preterm infant,. The optic disc detection is one of the fundamental step which could help to create an automate diagnose system for the doctors we use a new kind of active contour (snake) method has been developed by Chenyang et. al. [1], based on a new type of external force field, called gradient vector flow, or GVF. GVF is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. The testing results on a set of infant retinal ROP images verify the effectiveness of the proposed methods. We show that GVF has a large capture range and it's able to move snakes into boundary concavities of optic disc and finally the optic disk boundary was determined.

• Journal of the Optical Society of Korea
• /
• 제17권1호
• /
• pp.68-72
• /
• 2013

We developed an SD-OCT (Spectral Domain-Optical Coherence Tomography) system which uses a GPU (Graphics Processing Unit) for processing. The image size from the SD-OCT system is $1024{\times}512$ and the speed is 110 frame/sec in real-time. K-domain linearization, FFT (Fast Fourier Transform), and log scaling were included in the GPU processing. The signal processing speed was about 62 ms using a CPU (Central Processing Unit) and 1.6 ms using a GPU, which is 39 times faster. We performed an in-vivo retinal scan, and reconstructed a 3D visualization based on C-scan images. As a result, there were minimal motion artifacts and we confirmed that tomograms of blood vessels, the optic nerve, and the optic disk are clearly identified. According to the results of this study, this SD-OCT can be applied to real-time 3D display technology, particularly auxiliary instruments for eye operations in ophthalmology.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1993년도 추계학술대회
• /
• pp.27-30
• /
• 1993

Information about retinal blood vessels can be used in grading disease severity or as part of the process of automated diagnosis of diseases with ocular menifestations. In this paper, we address the problem of detecting retinal blood vessels and optic disk (papilla) in Eye-fundus images. We introduce an algorithm for feature extraction based on Fuzzy festering(FCM). The results ore compared to those obtained with other methods. The automatic detection of retinal blood vessels and optic disk in the Eye-fundus images could help physicians in diagnosing ocular diseases.

• 한국자동차공학회논문집
• /
• 제7권9호
• /
• pp.97-104
• /
• 1999

Brake squeal noise has been a problem since the early days of motoring . It is important to obtain vibration mode shape for reduction of brake noise . Stroboscopic Electronic Speckle Pattern Interferometry is a very powerful measuring method for study of vibrating objects in static state compared with conventional methods because this method can give both resonance frequency and quantitative visualization of vibration mode shape at the same time. In this paper, we performed qualitative visualization and quantitative analysis of vibration mode shpae of disk brake by using stroboscopic ESPI and phase shifting method. The stroboscopic wavefronts are obtained by chopping continuous wave laser beam using acousto-optic modulator .Experiments were performed at the same constraint conditions as disk brake of the practical vehicle as far as possible. The experimental results of this paper show quantitative measurement of vibration mode shape and quantiative visualization of vibration amplitude of disk brake with 3D plotting.

• 한국자기학회지
• /
• 제14권2호
• /
• pp.65-70
• /
• 2004

도메인 확장형 광자기 디스크 시스템(magnetic amplifing magnetooptical system; MAMMOS)의 기록마크 시뮬레이션을 위한 온도분포와 재생신호를 연구하였다. 정지된 디스크에서 레이저 빔에 의한 기록층과 이웃하는 층들의 온도 분포를 계산하였으며, 마크 크기와 길이 및 위치를 계산하였다. 또한 마크 모양에 따른 재생신호의 크기, 기록층에 기록되는 마크의 재생신호 및 판독층에서 확대된 재생신호를 시뮬레이션 하였다. 간소화된 열전달 특성 모델을 계산함으로써, 기록층과 인접한 층에서의 온도분포를 시간의 함수로 계산하였다. 마크 크기는 디스크가 회전할 때 기록 빔 펄스 파형에 의한 온도분포로부터 계산하였으며, 기록빔 펄스 파형으로부터 디스크의 온도분포를 이용하여 마크의 길이와 위치를 계산하였다. 재생신호는 디스크의 반사도 패턴과 가우시안 빔의 컨볼루션 연산을 이용하여 계산하였다. 판독층에서 빔 크기만큼 확대된 도메인의 재생신호가 기록층에서의 초승달 모양 마크에 기한 재생신호보다 2배 이상 증가되는 것을 알 수 있었다.

• 대한기계학회논문집A
• /
• 제28권3호
• /
• pp.245-250
• /
• 2004

This paper proposes a new method of measuring an air interface distance between a solid immersion lens(SIL) applied magneto-optic technology and the disk surface. For applying near-field recording (NFR) technology to the magneto-optic storage devices for the next generation, it is positively necessary to maintain the small air gap under about 100㎚. We design an apparatus that consists of some optical components such as a prism, a polarizer and an analyzer. By using the Fresnel reflection coefficient equation, Jones matrices calculation and Malus's law, we establish a mathematical model for understanding the characteristics of the system. The simulations are based on the mathematical model and through the simulation results which is made with various cases we can estimate the performance of the new optical gap sensor system. Experimental results, which are also based on the mathematical model for specific cases, are in good agreement with simulated ones and demonstrate the possibility as the new optical gap sensor.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.273-276
• /
• 1997

Seeing is an intelligent act. Retina is the most important part among the components of eye which is comprised of iris, pupil, lens, optic disk, and so forth. Because retina acts like a photo receiver to detect light from every object, if damaged, animals have a severe problem to live along with themselves and sometimes they lose their sight. In the ophthalmology, doctors use special instrument to see exact retina image of object and operate the surgery by rotating focus control knob. In this study, a basic test is done to achieve the auto focus control instrument. Specially made sledge and attenuator are installed on the optic bed to change the distance and laser power between the first reflective mirror and the second one. Control panel which is compiled by Visual C t t to control stepping motors ,laser power and photodiode are implemented with ADA-board.