• 대한전자공학회논문지SP
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• 제45권6호
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• pp.27-37
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• 2008

멀티미디어 기술과 콘텐츠의 발달로 3차원 데이터의 사용 범위가 넓어지고, 이를 보다 효율적으로 관리하고 검색하기 위한 시스템이 필요하다. 본 논문은 효율적인 3차원 모델의 형상 기반 검색을 하기위해 모델의 특징을 추출하는 단면 형상 영상 방법을 제안한다. 3차원 모델의 특징 기술자는 모델에 대한 위치, 회전, 크기에 불변해야 하므로 모델을 정규화 시키는 작업이 필요하다. 본 논문에서는 주성분 분석 방법을 이용하여 정규화하였다. 제안한 알고리즘은 주성분 분석을 통해 각 축의 방향 성분을 찾고, 각 축에 직교하는 n 개의 평면을 생성한다. 이 평면은 각 축의 방향과 직교 성분을 갖으며 단면 형상 영상을 구하는데 사용된다. 단면 형상 영상은 3차원 모델과 각 평면이 교차해서 생기는 2차원 평면 영상이다. 제안한 3차원 모델의 특징 기술자는 단면 형상 영상의 중심점과 2차원 형상(shape)을 이루는 직선까지의 유클리디안 거리(distance)값들의 분포도이다. 검색 성능 평가는 MPEG-7에서 제시한 표준 평가 방법인 표준화된 수정 검색 순위의 평균(ANMRR)을 이용하였고 제안한 방법의 우수성을 실험 결과를 통해 입증하였다.

• 한국정밀공학회지
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• 제17권5호
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• pp.76-83
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• 2000

Shape reconstruction is considered as a new technology to be useful and important in many areas such as RPD (Rapid Product Development) and reverse engineering, compared with the conventional design and manufacturing. In shape reconstruction, it becomes possible to reconstruct objects not by their measured shape data but those data extracted from the original shape. The goal of this research is to realize 3D shape construction by showing a possible way to analyze the input image data and reconstruct that original shape. The main 2 steps of the reconstructing process are getting cross-section data from image processing and linking loops between one slice and the next one. And the reconstructed object in this way is compared with the other object using a laser scanner and modelled by an commercial software.

• 한국정보기술학회논문지
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• 제15권12호
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• pp.165-171
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• 2017

본 논문은 서포터 생성 기법으로 형태학적 기하학 연산을 대신하여 층 단면 영상에 형태학적 영상 처리를 적용함으로 서포터를 생성하는 방법을 제안하였다. 기하학적 연산 비용은 일반적으로 형태에 의존적이지만 본 방법은 영상 내의 형태에 무관하게 적용된다. 돌출부에 대한 외부 서포터 영역을 얻는 방법으로 2개의 층 단면 영상에 대한 형태학적 영상 처리 방법 및 처리 과정의 예를 보였다. 내부 서포터 영역에 대하여 하나의 층 단면으로부터 침식과 열림을 통해 얻는 과정을 나타내었다. 그리고 이러한 서포터 영역을 얻고 서포터 구조를 통한 서포터를 생성하였다. 이어서 제작한 DLP 프린터에 서포터 구조를 가진 조형물을 제작하였다. 또, 서포터 형태에 따라 조형되는 소재의 특성이 조형에 주는 변화를 통해 소재에 따른 개별적인 서포터 구조를 통한 서포터 생성 방법의 필요성을 확인하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.146-151
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• 2000

The importance of shape reconstruction is increasing in many areas such as RPD(Rapid Product Development) and reverse engineering. Typical data in these areas are mainly classified as the shape data measured by a laser scanner and the data extracted from the CT image. The goal of this research is to realize three-dimensional shape construction by showing a possible way to analyze input image data and reconstruct the original shape. Two main steps of the reconstructing process are obtaining cross-section data from image processing and linking loops between one slice and the next. Objects reconstructed in this way are compared with other objects using a laser scanner and modelled by commercially available software. The technique is expected to be used in reverse engineering applications and the object modeling with automated process.

• Journal of Biosystems Engineering
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• 제26권6호
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• pp.545-552
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• 2001

Nondestructive methods such as ultrasonic and magnetic resonance imaging systems have many advantages but still much expensive. And they do not give exact color information and may miss some details. If it is allowed to destruct a biological object to obtain interior and exterior informations, 3D image visualization model from a series of sliced sectional images gives more useful information with relatively low cost. In this paper, a PC based automatic 3D visualization system is presented. The system is composed of three modules. The first module is the handling and image acquisition module. The handling module feeds and slices a cylindrical shape paraffin, which holds a biological object inside the paraffin. And the paraffin is kept being solid by cooling while being handled. The image acquisition modulo captures the sectional image of the object merged into the paraffin consecutively. The second one is the system control and interface module, which controls actuators for feeding, slicing, and image capturing. And the last one is the image processing and visualization module, which processes a series of acquired sectional images and generates a 3D volumetric model. To verify the condition for the uniform slicing, normal directional forces of the cutting edge according to the various cutting angles were measured using a strain gauge and the amount of the sliced chips were weighed and analyzed. Once the 3D model was constructed on the computer, user could manipulate it with various transformation methods such as translation, rotation, and scaling including arbitrary sectional view.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.658-663
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• 2003

A process of 3-D stereo particle image velocimetry(PIV)was developed for the measurement of an illuminated sliced section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transformation of the oblique-angled image to the right-angled image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criteria, and finally 3-D display as the post processing. An experimental system was also used for the application of the proposed method. Two high speed digital CCD cameras and an Argon-Ion Laser for the illumination were adopted to clarify the time-dependent characteristics of the leading edge extension(LEX) in a highly swept shape applied to a delta wing found in modern air-fighters.

• 한국정밀공학회지
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• 제23권11호
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• pp.116-125
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• 2006

MEMS and LIGA technologies have been used for fabricating microstructures, but their shape is not 3D because of difficulty for preparation of many masks. To fabricate 3D microstructures, microstereolithography technology based on Digital Micromirror Device($DMD^{TM}$) was introduced. It has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D parts are fabricated by layer-by-layer according to 2D section sliced from STL file. The UV light source is illuminated to DMD which makes bitmap images of 2D section, and they are transferred and focused on resin surface. In this paper, we addressed optical design of microstereolithography system in consideration of light path according to DMD operation and image-forming on the resin surface using optical design program. To verify the performance of implemented microstereolithography system, 3D microstructures with complexity and high aspect ratio were fabricated.

• 대한핵의학회지
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• 제30권1호
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• pp.1-14
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• 1996

Since the publication of the first bone scintiscans in 1962 three decades have elapsed. The bone scan has made great strides during this period, becoming one of the most commonly used nuclear imaging tests. In spite of the progress, however, the specificity of bone scan has remained relatively low. As the result it is a common practice to seek additional information from radiograph, CT scan and MR image, which is euphemistically termed as "image fusion or co-location." The basic reason is the inapplicability of the classical piecemeal analysis to interpreting planar and SPECT bone scans. Such analysis has its base on the observation of elemental features of morphology, which include the size, shape, contour, location, topography and internal architecture. The physiochemical profile may well also be included. Understandably, however, the miniatured images of the planar bone scan cannot provide these features in acceptable detail and the same holds true even with SPECT Images which are but sliced views of the reconstructed planar scans. Fortunately pinhole scanning has the capacity to portray both the morphological and chemical profiles of bone and joint diseases in greater detail through true magnification. The magnitude of pinhole scan resolution is practically comparable to that of radiography as far as gross anatomy is concerned. Thus, we feel strongly that pinhole scanning is a potential breakthrough of the long-lamented low specificity of bone scan. This presentation will discuss the fun-damentals, advantages and disadvantages and the most recent advances of pinhole scanning. It high-lights the actual clinical applications of pinhole scanning in relation to the diagnosis of infective and inflammatory diseases of bone and joint.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1214-1218
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• 2005

As demands for precision parts are increased, existing methods to fabricate them such as MEMS, LIGA technology have the technical limitations like high precision, high functionality and ultra miniaturization. A micro-stereolithography technology based on $DMD^{TM}$(Digital Micromirror Device) can meet these demands. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D part is fabricated by stacking layers that are sliced as 2D section from STL file. Whereas in conventional method, the resin surface is cured as scanning laser beam spot according to the section shape, but in this research, we use integral process which enables to cure the resin surface at one time. In this paper, we deal with the dynamic pattern generation and $DMD^{TM}$ operation to fabricate micro structures. Firstly, we address effective slicing method of STL file, conversion to bitmap, and dynamic pattern generation. Secondly, we suggest $DMD^{TM}$ operation and optimal support manufacturing for $DMD^{TM}$ mounting. Thirdly, we examine the problems on continuous stacking layers, and their improvements in software aspects.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.273-281
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• 2013

Purpose: This study was performed to evaluate the general anatomy and morphology of the nasopalatine canal using cone-beam computed tomography (CBCT) and to determine the human anatomic variability of the nasopalatine canal in relation to age and gender. Materials and Methods: The study included 100 subjects aged between 20 and 86 years who were divided into the following 3 groups: 1) 20-34 years old; 2) 35-49 years old; 3) ${\geq}50$ years old. The subjects were equally distributed between the genders. CBCT was performed using a standard exposure and patient positioning protocol. The data of the CBCT images were sliced in three dimensions. Image planes on the three axes (X, Y, and Z) were sequentially analyzed for the location, morphology and dimensions of the nasopalatine canal by two independent observers. The correlation of age and gender with all the variables was evaluated. Results: The present study did not reveal statistically significant differences in the number of openings at the nasal fossa; diameter of the nasal fossa openings; diameter of the incisive fossa; shape, curvature, and angulation of the canal as viewed in the sagittal sections; antero-posterior dimensions and length of the canal in the sagittal sections; or the level of division of the canal in the coronal plane by age. However, males and females showed significant differences in the length of the canal in the sagittal sections and level of the division of the canal in the coronal plane. Conclusion: The present study highlighted important variability observed in the anatomy and morphology of the nasopalatine canal.