• 산업공학
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• 제12권2호
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• pp.205-209
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• 1999

In reverse engineering area, the reconstruction of surfaces from scanned or digitized data is being developed, but geometric model of existing objects is not available in industries. This paper presents the new approach to the reconstruction of surface technique. A proposed methodology finds base geometry and blends surface between them. Each based geometry is divided by tri-angular patches which are compared with their normal vector for face grouping. Each group is categorized analytical surface such as a part of cylinder, sphere and cone, and plane shapes to represent the based geometry surface. And then, each based geometry surface is implemented to the infinitive surface. Infinitive surface's intersections are trimmed by boundary representation model reconstruction. This method has several benefits such as time efficiency and automatic functional modeling system in reverse engineering. Especially, it can be directly applied 3D fax and 3D copier.

• 방송공학회논문지
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• 제27권2호
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• pp.207-215
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• 2022

최신 볼류메트릭 기술이 제공하는 높은 기하학적 정확도와 사실성은 실제 객체와 캡춰된 3D 모델 간 높은 일치도를 보장한다. 그럼에도 불구하고 이렇게 획득된 3D 모델은 프레임 간 완전히 독립적인 3D모델로 시퀀스를 구성하고 있다는 측면에서, 매 프레임 모델 표면 구조(Geometry)의 일관성이 보장 되지 않으며, 정점(Vertex)의 밀도가 매우 높고 정점 간 연결 노드(Edge)가 매우 복잡해지는 특징을 확인 할 수 있다. 이 기술을 통해 생성된 3D 모델은 영화나 비디오 게임 제작 파이프라인에서 제작된 모델과는 본질적으로 다르며, 실시간 렌더링, 애니메이션 및 시뮬레이션, 압축과 같은 응용 분야에서 직접 사용하기에 적합하지 않다. 이와는 대조적으로 우리의 방법은 프레임 간 3D 모델 표면 구조의 높은 일관성을 확보하는 리메싱(Remeshing)과 비강체 표면(Non-rigid Shape)의 대응(Correspondences) 및 매칭(Matching)을 통한 점진적 변형(Deformation) 과정 및 텍스쳐 전달(Texture Transfer) 과정을 연결함으로서 볼류메트릭 3D 모델 시퀀스 품질의 일관성을 유지하며, 후 처리 과정의 자동화를 제공한다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.529-534
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• 2004

The increasing need and use of 3D GIS particularly in urban areas has produced growing attention on building reconstruction. Nowadays, the use of close-range data for building reconstruction has been intensively emphasized since they can provide higher resolution and more complete coverage than airborne sensory data. We developed a fusion approach for building reconstruction from both points and images. The proposed approach was then applied to reconstructing a building model from real data sets acquired from a large existing building. Based on the experimental results, we assured that the proposed approach cam achieve high resolution and accuracy in building reconstruction. The proposed approach can effectively contribute in developing an operational system producing large urban models for 3D GIS.

• 지구물리와물리탐사
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• 제16권1호
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• pp.27-35
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• 2013

본 연구를 통하여 3차원 자력역산 소프트웨어 시작품(KMag3D, 가칭)을 개발하고 개발 시 역점사항을 사용자 매뉴얼 형식으로 소개하였다. KMag3D는 다음 두 가지 사항을 기본 뼈대로 구성되었다. 첫째, 지금까지 자력역산에 일반적으로 적용되는 최소제곱법에 의한 방법 대신 대수적 재구성법에 기반한 알고리즘을 도입하였다. 이는 계산시간과 기억용량을 획기적으로 줄여 3차원 자력역산을 매우 효율적으로 수행한다. 둘째, 대수적 재구성법에 의한 3차원 역산에 필요한 초기모형과 사전정보 모형을 결정하는 데 2차원 수치모델링 및 역산 집합과 주향방향 내삽을 이용하는 방법을 제시하였다. 이는 3차원 역산 알고리즘에 사전정보를 효율적으로 적용하며 특히 매우 실용적임을 보여주었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.93-100
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• 2001

The three dimensional(3D) reconstruction from two dimensional(2D) image data is using in many fields such as RPD(Rapid Product Development) and reverse engineering. In this paper, the main step of 3D reconstruction is comprised of two steps : image processing step and B-spline surface approximation step. In the image processing step, feature points of each cross-section are obtained by means of several image processing technologies. In the B-spline surface approximation step, using the data of feature points obtained in the image processing step, the control points of B-spline surface are obtained, which are used for IGES file of 3D CAD model.

• Journal of International Society for Simulation Surgery
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• 제1권1호
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• pp.13-15
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• 2014

Nowadays, with advanced 3D printing techniques, the custom-made implant can be manufactured for the patient. Especially in skull reconstruction, it is difficult to design the implant due to complicated geometry. In large defect, an autograft is inappropriate to cover the defect due to donor morbidity. We present the process of manufacturing the 3D custom-made implant for skull reconstruction. There was one patient with skull defect repaired using custom-made 3D titanium implant in the plastic and reconstructive surgery department. The patient had defect of the left parieto-temporal area after craniectomy due to traumatic subdural hematoma. Custom-made 3D titanium implants were manufactured by Medyssey Co., Ltd. using 3D CT data, Mimics software and an EBM (Electron Beam Melting) machine. The engineer and surgeon reviewed several different designs and simulated a mock surgery on 3D skull model. During the operation, the custom-made implant was fit to the defect properly without dead space. The operative site healed without any specific complications. In skull reconstruction, autograft has been the treatment of choice. However, it is not always available and depends on the size of defect and donor morbidity. As 3D printing technique has been advanced, it is useful to manufacture custom-made implant for skull reconstruction.

• 한국정보통신학회논문지
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• 제14권11호
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• pp.2563-2568
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• 2010

합성 촬영 집적 영상 (synthetic aperture integral imaging; SAII) 기술은 하나의 카메라를 이동하여 3D 물체에 대한 다시점 영상을 획득하여 깊이 정보의 3D 영상을 복원이 가능한 기술이다. 이 방법은 크게 3D 물체의 요소 영상을 픽업하는 과정과 픽업된 요소 영상을 이용하여 컴퓨터 기반으로 3D 깊이 영상들을 복원하는 두 과정으로 나눈다. 본 논문에서는 이 SAII에 대한 신호 모델을 설명하고, 이를 통하여 발생하는 잡음을 정의하고 해석하였다. SAII에 대한 신호해석을 통하여 다시점 영상을 얻기 위한 카메라 이동 거리를 줄임으로써 영상 잡음감소와 계산 속도 개선을 동시에 얻을 수 있음을 보고한다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.159-160
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• 1998

In this study, a three-dimensional geometrical parameterized finite element modeling of the lumbar spine is compared with the 3-D reconstruction model from 2-D CT image. feasibility and accuracy of the parameterized modeling method is evaluated compared with conventional 3-D reconstruction method from 2-D CT image.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권5호
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• pp.226-232
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• 2001

The ability to efficiently and robustly recover accurate 3D terrain models from sets of stereoscopic images is important to many civilian and military applications. To develop an effective and practical terrain modeling system, we propose a new multi-image stereo method which detect unreliable elevations in DEM(Digital Elevation Map), and fuse several DEMs from multiple sources into an accurate and reliable results. This paper focuses on two key factors for generating robust 3D terrain models: the ability to detect unreliable elevation estimates and the ability to fuse the reliable elevations into a single optimal terrain model. We apply the self-consistency methodology to reconstruct accurate DEM from multi-image and show the method is more effective than the conventional stereo image 3D reconstruction method. Using photo-realistic simulator, four synthetic image are generated from ground truth DEM and orthoimage to evaluate the accuracy of the proposed method quantitatively.

• 전기전자학회논문지
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• 제12권1호
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• pp.51-58
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• 2008

This paper presents a new method for building detection and reconstruction from aerial images. In our approach, we extract the useful building location information from the generated disparity map to obtain the segmentation of interested objects and thus reduce significantly unnecessary line segment extracted in low level feature extraction step. Hypothesis selection is carried out by using undirected graph in which close cycles represent complete rooftops hypotheses, and hypothesis are finally tested to contruct building model. We test the proposed method with synthetic images generated from Avenches dataset of Ascona aerial images. The experiment result shows that the extracted 3D line segments of the buildings can be efficiently used for the task of building detection and reconstruction from aerial images.