• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.138-145
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• 2009

Custom medical treatment is being widely adapted to lots of medical applications. A technology for 3D modeling is strongly required to fabricate medical implants for individual patient. Needs on true 3D CAD data of a patient is strongly required for tissue engineering and human body simulations. Medical imaging devices show human inner section and 3D volume rendering images of human organs. CT or MRI is one of the popular imaging devices for that use. However, those image data is not sufficient to use for medical fabrication or simulation. This paper mainly deals how to generate 3D geometry data from those medical images. A new image processing technology is introduced to reconstruct 3D geometry of a human body vacancy from the medical images. Then a surface geometry data is reconstructed by using Marching cube algorithm. Resulting CAD data is a custom 3D geometry data of human vacancy. This paper introduces a novel 3D reconstruction process and shows some typical examples with implemented software.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.952-962
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• 2015

In this study, multilayered rings with a large outer diameter have been developed using a hot ring rolling process. The ring rolling process has been analyzed by rigid plastic finite element analyses (FEA) using the AFDEX2D and AFDEX3D/HEXA/RING simulators, where the finite element meshes received severe plastic deformation are remeshed into a fine mesh-size using a dual-mesh system. According to the simulated results, the design variables of the multilayered rings were determined and real tests were conducted to check the validity of the simulation results. By adopting the hot ring rolling process, the input weight of raw materials was reduced by 40% against the conventional hot forging process and that the recovery rate was increased by 24%. The measurement of the averaged roundness was satisfied within 0.5 mm for both the inner and outer diameters. Moreover, the hot ring rolling processes yielded 1.49 Cpk for the outer-diameter and 0.84 Cpk 0.84 for the inner-diameter.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.61-67
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• 1985

The new computer vision system which can reconstruct contours of parallel fault planes with horizon of 3-D curved objects has been developed. With the system, the shape of 3-D objects was measured by Simple Back-Projection algorithm which is a fundamental one in C.T.(Computed Tomography). And, the curvature in differential geometry characterizes any curve. Devising it, the method to represent each contour of 3-D curved objects with the system is described in this paper.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.1
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• pp.99-112
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• 1994

This paper describe the development of a systematic method of slicing solid parts based on a data structure called Sliced Profile Data Structure(SPDS). SPDS is an augmented polygon data structure that allows multiple layers of sliced profiles to be connected together. The method consists of five steps: (1) Selection of slicing directions, (2) Determination of slicing levels, (3) Creation of sliced profiles, (4) Connection of sliced profiles, and (5) Refinement. The presented method is aimed at enhancing the applicability of CSG for manufacturing by overcoming the problem of non-uniqueness and global nature. The SPDS-based method of feature extraction is suitable for recognizing broad scope of features with detailed information. The method is also suitable for identifying the global relationships among features and is capable of incorporating the context dependency of feature extraction.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.28-34
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• 2007

In design stage of vehicles, the application of virtual durability analysis techniques enables us to cut down the necessary time and cost to carry out various physical experiments. In this study, computer simulations of vehicle suspensions were carried out with DADS program including component flexibility, and the durability analysis of vehicle components was executed with MSC/Fatigue program using the load history obtained from vehicle dynamic simulation. Driving test of a vehicle was also carried out to obtain precise input data for the durability analysis, and the results of virtual durability analysis were compared to those of experiments.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1003-1004
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• 2008

In this paper, we propose a 3D modeling method using Laser Slit Beam and Stereo Camera. We can get depth information of image by analyzing projected Laser Slit Beam on object. 3D modeling is demanded exquisite merge of 3D data. In our approach, we can get the depth image where the reliability is high. Each reconstructed 3D modeling is combined by the sink information which is acquired by SIFT (Scale Invariant Feature Transform) Algorithm. We perform experiments using indoor images. The results show that the proposed method works well in indoor environments

• Proceedings of the Conference
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• 2005.12a
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• pp.40-47
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• 2005

카토그램(Cartogram)은 통계데이터를 이용하여 지리공간에 나타나는 현상을 효과적으로 표현하는 방법 중 하나이다. 카토그램이란 넓은 의미에서 모든 통계지도를 포함하지만, 좁은 의미에서 지도의 변형을 통해 통계데이터의 특징을 표현하는 시각화 방법을 의미한다. 이 연구에서는 후자의 의미에서 카토그램이란 용어를 사용하였으며, 우리나라를 대상으로 절대적 공간을 시간거리 접근성에 의한 공간 카토그램으로 재구성하여 지도화하고, 변화된 공간패턴을 분석하고자 하였다. 카토그램은 특정한 목적을 위해 기본도의 형상이나 지역간의 연속성을 강조시켜서 만든 변형된 지도의 일종으로 전통적인 지도와는 매우 다른 이미지를 주게 되지만, 표현하고자 하는 현상의 공간적 구조를 매우 효과적으로 나타낼 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.416-421
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• 1997

This study presents a way to construct 3D shape in STL format from 2D slice data. Nowadays ahape reconstruct has been done in many ares, the application of this method is important especially in Reverse Engineering which reconstructs original shape from cross-section data. Current RP (Rapid Prototyping) is used not only for the verification of a part designed but also for the production and tooling in more effective way. In RP technology, data should be prepared in STL format. In this paper, the way to make 3D shape data in STL format form 2D slice data is described which can be used to reconstruct an original shape in RP equipment.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.199-207
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• 1999

For the stress and vibration analysis of vehicle component by computer simulation, it is necessary to find the forces acting on the vehicle components due to the road profile undulation. A precise modeling of tires is not easy due to nonlinear effects between tire-ground. In this study, a new method is proposed to regenerate road profiles that preserves the same PSD of wheel with a linear tire model. Using the frequency response function between road-wheel , the digital signal processing method, and DADS program , road profile is regenerated from the computer simulation.

• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.19-25
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• 2012

The accuracy of Shape From Focus (SFF) technique depends on the quality of the focus measurements which are computed through a focus measure operator. In this paper, we introduce a new approach to estimate 3D shape of an object based on Gaussian process regression. First, initial depth is estimated by applying a conventional focus measure on image sequence and maximizing it in the optical direction. In second step, input feature vectors consisting of eginvalues are computed from 3D neighborhood around the initial depth. Finally, by utilizing these features, a latent function is developed through Gaussian process regression to estimate accurate depth. The proposed approach takes advantages of the multivariate statistical features and covariance function. The proposed method is tested by using image sequences of various objects. Experimental results demonstrate the efficacy of the proposed scheme.