• 한국안전학회지
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• 제18권4호
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• pp.98-104
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• 2003

Various nondestructive evaluation (NDE) techniques have been studied to locate steel rebars of dowel, and to detect invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes. In this study, the aurhors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars of dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna array was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. This paper presents the analytical expressions of numerical focusing procedures for 3D image reconstruction and numerical simulation to study the resolution of the system and the effectiveness of multi-frequency technique. Also, the design of 4?4 antenna array with switching devices is introduced as a preliminary study for the final design of whole array.

• Investigative Magnetic Resonance Imaging
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• 제11권2호
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• pp.87-94
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• 2007

목적: 3T 장비의 신생아 뇌자기공명영상에서 T1 강조 고속 역전회복기법 (fast inversion recovery, FIR)과 자기화 삼차원 경사에코기법, (magnetization-prepared three dimensional gradient echo sequence, 3D GRE)을 스핀에코기법 (SE)과 비교하여 유용성을 알아보는 데 있다. 대상 및 방법: 20명의 신생아에서 T1 강조 SE, FIR, 그리고 3D GRE의 신호소음비 (SNR)와 대조소음비 (CNR)를 측정하고 시각적으로 회백질-백질 구별, 수초화 인식, 인공음영 발생을 점수화하여 비교하였다. 각 영상기법의 CNR 비교에는 Wilcoxon signed ranked test를 사용하였다. 결과: 세가지 영상기법 중 3D GRE가 가장 우수한 SNR을 보였고 CNR은 FIR과 3D GRE 모두 SE보다 우수하였으며 FIR보다 3D GRE가 더 우수하였다. 회백질-백질의 구분과 수초화 유무 역시 스핀에코보다 FIR과 3D GRE에서 더 잘 보였다. 그러나 3D GRE는 움직임에 의한 인공음영이 많았고 FIR에서 혈류에 의한 혈관의 고신호강도가 자주 발견되었다. 결론: 3T 장비에서 신생아 뇌영상을 얻을 때 FIR과 3D GRE 기법은 SE보다 좋은 T1 강조영상을 제공할 것으로 기대된다.

• Journal of information and communication convergence engineering
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• 제13권2호
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• pp.132-138
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• 2015

Enlarging the horizontal viewing angle is an important feature of integral imaging monitors. Thus far, the horizontal viewing angle has been enlarged in different ways, such as by changing the size of the elemental images or by tilting the lens array in the capture and reconstruction stages. However, these methods are limited by the microlenses used in the capture stage and by the fact that the images obtained cannot be easily projected into different displays. In this study, we upgrade our previously reported method, called SPOC 2.0. In particular, our new approach, which can be called SPOC 2.1, enlarges the viewing angle by increasing the density of the elemental images in the horizontal direction and by an appropriate application of our transformation and reshape algorithm. To illustrate our approach, we have calculated some high-viewing angle elemental images and displayed them on an integral imaging monitor.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.155-157
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• 2012

본 논문에서는 집적 영상 기술에 기반한 컴퓨터 3D 영상 복원을 이용하여 비선형 3D 영상 상관기를 제안한다. 제안하는 방법에서는 먼저 기준 3D 물체와 목표 3D 물체의 요소 영상들을 렌즈 어레이를 통해 픽업한다. 이 픽업된 영상에 컴퓨터 집적 영상 복원 방법을 사용하여 목표 평면 영상과 기준 평면 영상들이 복원된다. 복원된 기준 평면 영상과 목표 평면 영상들 간의 비선형 상호상관을 통해 인식을 수행한다. 제안된 방법의 유용함을 보이기 위해 기존의 방법과 비교하여 기초적인 상관관계 실험을 수행하고 그 결과를 발표한다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.257-261
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• 1995

Confocal laser scanning microscopy (CLSM)는 기존의 coherent or incoherent microscopic imaging 보다 횡축 방향 (lateral direction)으로 고해상도를 가지며, 층과 층 사이를 구분하는 광축 방향 (axial direction)의 optical sectioning에 의해 샘플의 3D 구조를 고해상도로 영상화함으로써 3D 구조 및 생체 기능 분석을 가능하게 해 준다. 본 논문에서는 CLSM에 의한 3D 영상화 원리와 촛점면 부근에서 얻어지는 광세기 분포, 얻어진 2D slice 영상의 시각화 및 응용에 대해 논의된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1314-1317
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• 2006

The problem of the conflict between eye convergence and accommodation can be induced at Stereoscopic or multi-view 3D display system using binocular disparity. A multi-focus 3D display system was developed, which can solve the problem. LEDs are used instead of galvano scanner and laser to avoid mechanical moving part at the 3D display system.

• Journal of Information Display
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• 제11권2호
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• pp.68-75
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• 2010

The relation between light sources and screen cells is considered part of the theoretical model of an autostereoscopic 3D display. The geometry of the image and observer regions is presented, including the cases of single and multiple regions. The characteristic function is introduced. Formulas for the geometric parameters are obtained, including areas and angles. Special attention is drawn to the screen location. The method of transforming the formulas between regions is stated. For multiple regions, geometric dissimilarity was found. This allows the model to be applied in finding the geometric characteristics of multiview and integral-imaging 3D displays.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.506-508
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• 2002

As an advancement of medical imaging modalities and analyzing software with multi-function, active researches to acquire high contrast and high resolution image being done. In recently, development of medical imaging modalities like as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is aiming to display anatomical structure more accuracy and faster. Thus, one of the important areas in CT today is the use of CT scanner for the quantitative evaluation of 3-D reconstruction images from 2-D tomographic images. In CT system, the effective slice thickness and the quality of 3-D reconstructed image will be influenced by imaging acquisition parameters (e.g. pitch and scan mode). In diagnosis and surgical planning, the accurate distance measurements of 3-D anatomical structures play an important role and the accuracy of distance measurements will depend on the acquisition parameters such as slice thickness, pitch, and scan mode. The skull phantom was scanned with SDCT for various acquisition parameters and acquisition slice thicknesses were 3 and 5 mm, and reconstruction intervals were 1, 2, and 3 mm to each pitch. 3-D visualizations and distance measurements were performed with PC based 3-D rendering and analyzing software. Results showed that the image quality and the measurement accuracy of 3-D SDCT images are independent to the reconstruction intervals and pitches.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.3055-3062
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• 2014

동적 마스크를 사용하는 3D 집적영상 기술은 공간에 고해상도의 3D 영상을 디스플레이할 수 있다. 본 논문에서는 동적 마스크를 사용한 새로운 3D/2D 변환 집적영상 디스플레이 시스템을 제안한다. 제안하는 방법에 대하여 2개의 LCD 패널을 통하여 보여지는 영상에 따른 3D 모드, 2D모드 그리고 3D/2D 혼합 모드의 동작원리를 설명한다. 3D모드에서는 요소영상과 마스크 영상이 표시되고, 2D 모드에서는 광원영상과 2D 영상이 표시된다. 그리고 3D/2D 혼합모드에서는 영역별로 2D와 3D가 분리되어 동시에 디스플레이 된다. 제안한 방법의 유용함을 보이기 위해서 기초적인 실험을 수행하고 그 결과를 보고한다.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2004년도 제9차 학술대회 초록집
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• pp.23-32
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• 2004

The chemotherapy sensitive Lewis lung carcinoma (LLC) and chemotherapy resistant Lewis lung carcinoma (CR-LLC) tumors concurrently implanted in mice, and compare these findings with histological macroscopic observations against 3D reconstruction of Fluorescence Molecular Tomography (FMT) preformed in vivo on the same animals. For the 3D image reconstruction we used 32 laser source images, a flat image and 3D surface rendering that confused for 3D Fluorescence Molecular Imaging (FMI). A minimum of ten tissue sections were analyzed per tumor for quantification of the TUNEL-positive cells, cell-associated Cy5.5-Annexin and vessel-associated Alexa Fluor-Lectin. These are useful apoptosis and angiogenesis markers, and they serve as validation experiments to data obtained in vivousing a Cy5.5-Annexin V conjugate injected intravenously in chemotherapy-treated animals carrying the tumors studied histologically. We detected higher levels of apoptosis and corresponding higher levels of Cy5.5 fluorescence in the LLC vs. the CR-LLC tumors according to tissue depth and these findings confirm that in vivo staining with the Cy5.5-Annexing conjugate correlates well with in vitro TUNEL staining and is consistent with the higher apoptotic index expected from the LLC line. There appeared to be 1.38% more apoptosis for LLC than CR-LLC. Consequently there is good correlation between the histology results and in vivo fluorescence-mediated optical imaging. In conclusion the apoptotic images of 3D FMI were validated by microscopic histological image analysis. This is a significant result for the continuous progress of fluorescence 3D imaging research.