• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.05b
• /
• pp.389-392
• /
• 2003

MRI 영상은 뇌의 해부학적 정보와 기능적인 정보를 제공하는 유용한 도구이다. MR 뇌 영상은 2차원 영상뿐만 아니라 3차원 영상도 임상적으로 중요하다. MR 영상에서 뇌영역의 추출방법으로는 형태학적인 방법, 히스토그램을 이용한 방법, 에지 정보를 이용한 방법, 지식 기반을 이용한 방법들이 있다. 본 논문에서는 region growing을 이용하여 MR 영상에서 뇌 영역을 추출하였다. 3차원 가시화를 위하여 오픈 소스인 VTK를 이용하여 Ray Casting 알고리즘으로 구현하였다. 그리고 의료영상에서 사용되는 각종 단면을 3차원 뇌 영상에서 재구성하였다. 256×256 크기의 71 뇌MR 영상 70장을 이용하여 실험하였다. 향후 연구과제로 MR 영상에서 뇌 영역추출방법과 원영상의 전처리 과정의 연구가 필요하다.

• Journal of the Korean Society of Visualization
• /
• v.19 no.2
• /
• pp.48-55
• /
• 2021

In order to design a propeller with high efficiency and excellent cavitation performance, theoretical and experimental studies on the cavitation and noise characteristics according to the blade section shape are essential. In general, sheet cavitation, bubble cavitation, and cloud cavitation are the main causes of hull vibration and propeller surface erosion. However vortex cavitation, which has the greatest influence on the noise level because the fastest CIS in ship propeller, has been researched for a long time and studies have been conducted recently to control it. In this experiment, the development process of cavitation was measured by using three dimensional wings with two different wing section and wing tip shapes, and the noise level at that time was evaluated. In addition, we evaluated the relationship between cavitation inception and hydrodynamic force using three component load cell and we measured the velocity field of wing wake using LDV.

• KIISE Transactions on Computing Practices
• /
• v.23 no.12
• /
• pp.660-669
• /
• 2017

In order to improve user accessibility and interactivity, system scalability, service speed, and a non-standard internet web environment, we developed a Web-based geovisualization system of oceanographic information using HTML5 and dynamic particles. In particular, oceanographic and meteorological data generated from a satellite remote sensing and radar measurement and a 3-dimensioanl numerical model, has the characteristics of a heterogeneous large-capacity multi-dimensional continuous spatial and temporal variability, based on geographic information. Considering those attributes, we applied dynamic particles represent the spatial and temporal variations of vector type oceanographic data. HTML5, WebGL, Canvas, D3, and Leaflet map libraries were also applied to handle various multimedia data, graphics, map services, and location-based service as well as to implement multidimensional spatial and statistical analyses such as a UV chart.

• Journal of the Korean Society of Visualization
• /
• v.1 no.1
• /
• pp.92-97
• /
• 2003

A new Stereoscopic PTV was developed using two CCD cameras, stereoscopic photogrammetry based on a 3D-PTV principle. Virtual images were produced for the benchmark test of the constructed Stereoscopic PTV technique. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on the Genetic Algorithm based 3D-PTV technique. The constructed Stereoscopic PTV technique was tested on the standard images of the impinged jet proposed by VSJ. The results obtained by the constructed system showed good agreements with the original data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.04a
• /
• pp.490-495
• /
• 2009

An approach to 3D visualization of multiple sound sources has been developed with the application of a moving array technique. Frequency-domain beamforming algorithm is used to generate a beam power map and the sound source is modeled as a point source. When a conventional delay and sum beamformer is used, it is considered that 2D distribution of sensors leads to have deficiency in spatial resolution along a measurement distance. The goal of moving an array in this study is to form 3D array aperture surrounding multiple sound sources so that the improved spatial resolution in a virtual space can be expected. Numerical simulation was made to examine source localization capabilities of various shapes of array. The 3D beam power maps of hemispherical and spherical distribution are found to have very sharp resolution. For experiments, two sound sources were placed in the middle of defined virtual space and arc-shaped line array was rotated around the sources. It is observed that spherical array show the most accurate determination of multiple sources' positions.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.9
• /
• pp.907-914
• /
• 2009

An approach to 3D visualization of multiple sound sources has been developed with the application of a moving array technique. Frequency domain beamforming algorithm is used to generate a beam power map and the sound source is modeled as a point source. When a conventional delay and sum beamformer is used, it is considered that 2D distribution of sensors leads to have deficiency in spatial resolution along a measurement distance. The goal of moving an array in this study is to form 3D array aperture surrounding multiple sound sources so that the improved spatial resolution in a virtual space can be expected. Numerical simulation was made to examine source localization capabilities of various shapes of array. The 3D beam power maps of hemispherical and spherical distribution are found to have very sharp resolution. For experiments, several sound sources were placed in the middle of defined virtual space and arc-shaped line array was rotated around the sources. It is observed that spherical array shows the most accurate determination of multiple sources' positions.

• Journal of the Korean Society of Visualization
• /
• v.6 no.2
• /
• pp.3-8
• /
• 2008

A new 3D-PTV algorithm(a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter(d=10 mm) are 360, 540, 720, 900, 1080 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image condition.

• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.347-351
• /
• 2010

In this paper, our effort to apply 3-D Virtual Reality system for stereoscopic visualization of flow data is briefly described. This study is an extension of our previous and on-going research efforts to develop DATA(Data Analysis and Visualization Application) program, which is a data visualization program developed by using Qt as GUI development environment and OpenGL as graphic library. The program is developed upon the framework of object-oriented programming and it was originally developed by using Qt 3.3.3 environment. In this research the program is converted into a Qt 4.3.3-compatible version, and this new version is developed on Visual Studio 2005. And to achieve a stereoscopic viewing capability, two graphic windows are used to render its own viewing image for the lift and right eye respectively. These two windows are merged into one image using 3D monitor and the viewers can see the data visualization results with stereoscopic depth effects by using polarizing glasses. In this paper three dimensional data visualization with stereoscopic technique combined with 3D Monitor is demonstrated, and the current achievement would be a good start-up for further development of low-cost high-quality stereoscopic data visualization system.

• CDE review
• /
• v.17 no.3
• /
• pp.18-21
• /
• 2011

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.02a
• /
• pp.499-504
• /
• 2000