• 한국지능시스템학회논문지
• /
• 제9권4호
• /
• pp.436-443
• /
• 1999

대부분의 3차원 물체 복원 기술은 물체를 다수의 평면으로 나누고 물체의 각 표면을 근사시켜 표현한다. 주어진 분류치를 사용하여 mesh를 초기화시키는 Marching Cubes 알고리듬과 Delaunay Tetrahedrisation이 널리 사용되고 있다. 이와 더불어 deformable 모델은 적은수의 가정만으로도 다양한 종류의 데이터들에 대한 복원 및 재구성을 할수 있기 때문에 일반적인 물체복원에 적합하다. 현재 defrmable 모델이 기반이 된 복원 시스템에 대한 연구가 활발히 진행중이다. 본 논문에서는 곡면으로 이루어진 물체에 대해서 적응 simplex mesh 기술을 바탕으로 3차원 물체를 압축 복원하는 방법을 제시한다. 이방법은 미리 정해진 mesh 구조를 변형시키고 곡률과 같은 기하학적인 특성들을 다시 설정하면서 본래의 3차원 물체로 접근시킨다. 시뮬레이션을 통해서 높은 압축률로 물체를 복원하고 물체의 모양을 최적으로 기술하기 위해 정점들이 곡률이 높은 곳으로 집중되는 것을 보인다.

• Journal of International Society for Simulation Surgery
• /
• 제1권1호
• /
• pp.32-36
• /
• 2014

Reconstruction of the maxilla is quite a difficult challenge for reconstructive surgeons. The maxilla is the most important part of the midface, which contributes to facial esthetics, mastication, swallowing, speech, supporting orbital contents and sinus function. Free fibular flap is most versatile to reconstruct jaw bone because of its adequate length, containing both soft and bony tissues and acceptance of dental implants. In this case report, a reconstruction of the maxilla using free fibular flap and dental implants is described in which rapid prototype was used before surgery to simulate the final prosthetic results.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 추계학술대회 논문집
• /
• pp.993-994
• /
• 2010

• 한국CDE학회논문집
• /
• 제15권4호
• /
• pp.297-305
• /
• 2010

Medical image acquisition techniques such as CT and MRI have disadvantages in that the numerous time and efforts are needed. Furthermore, a great amount of radiation exposure is an inherent proberty of the CT imaging technique, a number of side-effects are expected from such method. To improve such conventional methods, a number of novel methods that can obtain 3D medical images from a few X-ray images, such as algebraic reconstruction technique (ART), have been developed. Such methods deform a generic model of the internal body part and fit them into the X-ray images to obtain the 3D model; the initial shape, therefore, affects the entire fitting process in a great deal. From this fact, we propose a novel method that can generate a 3D vertebraic generic model based on the statistical database of CT scans in this study. Moreover, we also discuss a method to generate patient-tailored generic model using the facts obtained from the statistical analysis. To do so, the mesh topologies of CT-scanned 3D vertebra models are modified to be identical to each other, and the database is constructed based on them. Furthermore, from the results of a statistical analysis on the database, the tendency of shape distribution is characterized, and the modeling parameters are extracted. By using these modeling parameters for generating the patient-tailored generic model, the computational speed and accuracy of ART can greatly be improved. Furthermore, although this study only includes an application to the C1 (Atlas) vertebra, the entire framework of our method can be applied to other body parts generally. Therefore, it is expected that the proposed method can benefit the various medical imaging applications.

• 한국정밀공학회지
• /
• 제19권7호
• /
• pp.71-79
• /
• 2002

A new rapid prototyping process, Variable Lamination Manufacturing using a 4-axis-controlled hotwire cutter and expandable polystyrene foam sheet as a laminating material of the part (VLM-S), has been developed to reduce building time and to improve the surface finish of parts. The objective of this study is to reconstruct the surface of the original 3D CAD model in order to generate mid-slice data using the advancing front technique. The generation of 3D layers by a 4 axis-controlled hot-wire cutter requires a completely different procedure to generate toolpath data unlike the conventional RP CAD systems. The cutting path data for VLM-S are created by VLM-Slicer, which is a special CAD/CAM software with automatic generation of 3D toolpath. For the conventional sheet type system like LOM, the STL file would be sliced into 2D data only. However, because of using the thick layers and a sloping edge with the firstorder approximation between the top and bottom layers, VLM-Slicer requires surface reconstruction, mid-slice, and the toolpath data generation as well as 2D slicing. Surface reconstruction demands the connection between the two neighboring cross-sectional contours using the triangular facets. VLM-S employs thick layers with finite thickness, so that surface reconstruction is necessary to obtain a sloping angle of a side surface and the point data at a half of the sheet thickness. In the process of the toolpath data generation the surface reconstruction algorithm is expected to minimize the error between the ruled surface and the original parts..

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 추계 학술논문 발표대회
• /
• pp.183-184
• /
• 2015

More than 50% of the existing buildings in Korea are over 15 years old. Therefore it is necessary to be held reconstruction or remodeling deteriorated buildings more efficiently. Especially, since remodeling project reserves existing structures, it requires less period of project and construction period compare to reconstruction. It is possible to minimize uncertainty in communication between participants and able to manage information and construct efficiently in remodeling projects. This paper is first step of integrated BIM-based whole lifecyle management of apartment remodeling process. It suggests 3D laser scanner specification factors and site constraint factors for mapping between two groups. Therefore it will contribute to develop mapping algorithm of two groups and find optimal combination for apartment remodeling.

• Journal of Mechanical Science and Technology
• /
• 제17권11호
• /
• pp.1665-1673
• /
• 2003

We propose an image-based three-dimensional shape determination system. The shape, and thus the three-dimensional coordinate information of the 3-D object, is determined solely from captured images of the 3-D object from a prescribed set of viewpoints. The approach is based on the shape-from-silhouette (SFS) technique, and the efficacy of the SFS method is tested using a sample data set. The extracted three-dimensional shape is modeled with polygons generated by a new iterative triangulation algorithm, and the polygon model can be exported to commercial software. The proposed system may be used to visualize the 3-D object efficiently, or to quickly generate initial CAD data for reverse engineering purposes, including three dimensional design applications such as 3-D animation and 3-D games.

• Current Optics and Photonics
• /
• 제2권4호
• /
• pp.332-339
• /
• 2018

A new multi-frequency fringe projection method is proposed to reduce the nonlinear phase error in 3-D shape measurements using an adaptive compensation method. The phase error of the traditional fringe projection technique originates from various sources such as lens distortion, the nonlinear imaging system and a nonsinusoidal fringe pattern that can be very difficult to model. Inherent possibility of phase error appearing hinders one from accurate 3-D reconstruction. In this work, an adaptive compensation algorithm is introduced to reduce adaptively the phase error resulting from the fringe projection profilometry. Three different frequencies are used for generating the gratings of projector and conveyed to the four-step phase-shifting procedure to measure the objects of very discontinuous surfaces. The 3-D shape results show that this proposed technique succeeds in reconstructing the 3-D shape of any type of objects.

• 전자공학회논문지SC
• /
• 제45권6호
• /
• pp.26-34
• /
• 2008

차량의 접근 가능한 구역에 대한 판단과 경로 계획은 무인 차량의 자율 주행에 있어서 필수적이다 차량의 접근 가능한 구역과 경로계획을 위한 정보는 3차원 지형형상을 분석하여 얻을 수 있다. 이 논문에서는 카메라의 색 정보와 2차원 레이저 거리센서(2D LRF)를 융합하여 모바일 로봇의 휠 인코더를 통해 복원한 3차원 지형형상과, GPS/IMU 정보와 2차원 레이저 거리 센서로 복원한 3차원 지형형상을 적은 데이터로 표현하는 방법을 제시하였다. 카메라의 색 정보와 2차원 레이저 거리센서의 융합을 위해 카메라의 좌표계와 LRF의 좌표계 사이의 기하학적인 관계를 격자무의 평면을 이용하여 구하였다. 카메라와 2차원 레이저 거리센서의 융합을 통한 3차원 지형형상 복원은 모바일 로봇을 이용하여 실내에서 실험하였고, GPS/IMU 정보와 2차원 레이저 거리센서를 통한 3차원 지형형상 복원은 차량을 이용하여 실외에서 실험하였다. 이런 시스템에서 복원한 3차원 지형형상은 점군 기반으로 되어있고, 이는 매우 많은 양의 정보를 필요로 한다. 정보의 양을 줄이기 위해 점군 기반을 대신하여 입방형 격자 기반의 지형형상으로 복원하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 추계종합학술대회 논문집
• /
• pp.927-930
• /
• 1998

This paper presents a new method for reconstructing 3 dimensional object model using a zoom camera. The proposed method uses zoom images to find the distance(D) between camera and object. Also the method uses images obtained around the object to find an $angle(\theta)$ between two connected planes of the object. With the D and $\theta,$ we can reconstruct the real sized 3-D model of object with less errors without stereo camera or rangefinder.