• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.113-117
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• 2015

This study presents a 3-dimensional flow-structure interaction analysis of subsea risers in water flows. Two structural connectors (flat and circular couplers) were intentionally devised and numerically tested using ANSYS CFX to investigate how these couplers behave under the water flows. In the flow analysis, the water field was constructed with an inlet, outlet, and symmetric boundary conditions. As a result, the responses (drag coefficients and pressure fields) were obtained and the pressure fields were applied for the structural analysis. Finally, the structural responses (displacements and equivalent stresses) of the risers were measured to demonstrate the efficiency of the riser connectors.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.89-96
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• 2007

In this paper, we designed 3D graphics rasterizer with a culling and clipping for the efficient 3D graphics accelerator. The proposed rasterizer is implemented for the mobile system and process frustum culling, back face culling, Y-axis clipping and X-axis clipping. The rasterzier consists of triangle setup, edge walk and span process unit. Each unit of rasterzier is designed with a culling and clipping. It supports goraud shading with 16 bits depth values and 16 bits color values. The estimated performance of proposed rasterizer is 52M pixels per second.

• Journal of KIISE:Software and Applications
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• v.31 no.7
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• pp.922-928
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• 2004

We propose a new 3 dimensional labeling method based on slice information for the volume data. This method is named SIL (Slice Information based Labeling). Compare to the conventional algorithms, it has advantages that the use of memory is efficient and it Is possible to combine with a variety of 2 dimensional labeling algorithms for finding an appropriate labeling algorithm to its application. In this study, we applied SIL to confocal microscopy images of cervix cancer cell and compared the results of labeling. According to the measurement, we found that the speed of Sd combined with, CCCL (Contour based Connected Component Labeling) is almost 2 times higher than that of other methods. In conclusion, considering that the performance of labeling depends on a kind of image, we obtained that the proposed method provide better result for the confocal microscopy cell volume data.

• Journal of IKEEE
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• v.23 no.1
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• pp.44-52
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• 2019

We implement an educational indoor autonomous mobile robot system that integrates LiDAR sensing information with RGB-D camera image information and exploits the integrated information. This system uses the existing sensing method employing a LiDAR with a small number of scan channels to acquire LiDAR sensing information. To remedy the weakness of the existing LiDAR sensing method, we propose the 3D structure recognition technique using depth images from a RGB-D camera and the deep learning based object recognition algorithm and apply the proposed technique to the system.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.275-278
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• 2001

영상 분할은 임상에서의 진단과 분석 및 3차원 가시화하는데 있어 선행되어야 할 필수적인 과정이다. 본 논문에서는 심혈관계 영상의 분할을 위한 Wave-front SRG방법을 제안한다. 제안된 방법은 2차원 슬라이스 영상에서 사용자에 의한 씨앗점(seed front)을 입력으로 받아 그 이웃한 슬라이스들에 wave-front를 만들어 영역 성장법에 의해 3차원 volume을 확장시킨다. 이때 다음으로 성장할 wave-front voxel의 mean gradient 값을 사용하여 밝기값의 변화가 심한 심혈관계 영상을 분할하였으며, Wave-front voxel의 size를 계산하여 혈관분할 시 발생할 수 있는 작은 채널에서의 새나감을 방지하였다. 제안된 방법을 컴퓨터 단층촬영으로 얻은 심혈 관계 영상의 분할에 적용한 결과, 밝기값의 변화가 심한 심혈관계 영상을 성공적으로 분할했으며, 작의 채널의 새나감이 없이 분할을 수행하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.763-766
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• 2002

오늘날 CT나 MR 등을 통한 의학 영상 기술과 컴퓨터 성능의 향상으로 인체 내부 장기의 영상을 비교적 용이하게 얻을 수 있으며 얻어진 영상 정보는 컴퓨터로 수치화되므로 데이터의 조작 및 가공 또한 용이하다. 그러나, 이 데이터는 2D 슬라이스(slice)들의 연속으로 표현되므로 이것을 보다 가시화, 조작, 분석이 용이한 상태로 바꾸기 위해서는 3 차원 구조로의 재구성이 필요하게 된다. 이것을 위하여 무엇보다도 먼저 CT 나 MR 을 통하여 얻어진 영상을 분석하여 특정장기(organ)의 영상 부분을 다른 조직의 영상부분으로부터 분리(segmentation)할 필요가 있다. 이러한 Segmentation방법에는 여러가지가 있는데, 수작업의 결합 등으로 인해서 비효율적일 수 밖에 없는 문제점을 가지고 있다. 이에 본 논문은 보다 효율적인 segmentation 의 처리를 위하여 구역확장(region-growing) 기법을 응용한 새로운 segmentation 방법을 개발하였다. 그리하여, 본 논문이 제안한 알고리즘을 슬라이스 간격이 큰 2 차원 복부 CT 영상에 적용시켜 간(liver)의 추출을 시도하였고 3차원 표현 결과를 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.88-89
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• 2022

라이다 센서는 최근 다양한 산업에서 3 차원 물체의 식별을 위해 사용되고 있다. 주요 시설이나 전시관의 경계를 위해서 스캔형 라이더는 넓은 범위의 감지를 할 수 있지만 입력 데이터가 많아 물체의 식별과 관련된 연산이 오래 걸리는 문제를 가진다. 이러한 문제를 해결하기 위해서 제안하는 방법에서는 라이다 데이터를 간략화 하고 감지 이벤트를 통해 사용자들에게 알려줄 수 있도록 하는 알고리즘을 제안한다.

• Spatial Information Research
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• v.22 no.1
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• pp.1-7
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• 2014

In this paper, we suggested plan that utilize the mobile mapping system data for constructing 3D cadastral information of roads and buildings effectively. 3D cadastral information means conflation of existing cadastral information and spatial information. It also means 3D land management that can register and manage various spatial information with land information effectively. Technically, geometry information and attribute information by image or radar scanner and location information of geographic features calculated by GPS/INS integration technology are useful for constructing 3D cadastral information included in buildings and features on the ground. As a result, the application of mobile mapping system for constructing 3D cadastral information will make a scientification and enhancing of the land information.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.549-557
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• 2022

Tunnel face mapping involves the determination of rock discontinuities or weak rock conditions where extra support might be required. In this study, we investigated the application of Lidar scanning and photogrammetry to quantitatively characterize discontinuities of the rock mass on the tunnel face during excavation. The 3D models of tunnel faces generated by using these methods enable accurate and automatic discontinuity measurement to overcome the limitations of manual mapping. The results of this study show that both photogrammetry and Lidar can be used to reconstruct the 3D model of the tunnel face, although the photogrammetric 3D model is less detailed than its counterpart produced by Lidar. Given acceptable accuracy and cost-effectiveness, photogrammetry can be a fast, reliable, and low-cost alternative to Lidar for acquiring 3D models and determining rock discontinuities on tunnel faces.

• Progress in Medical Physics
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• v.14 no.2
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• pp.131-140
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• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.