• 한국정보통신학회논문지
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• 제20권2호
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• pp.281-288
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• 2016

움직임이 자연스러운 피사체는 대부분 형태가 불규칙하게 변형되는 비정형(non-rigid) 형상이고, 그 종류 또한 매우 다양하게 존재하다. 비정형 형상 복원에 관한 기술은 영화나 게임 산업에서 최근 폭넓게 적용되고 있다. 그렇지만, 현실적인 접근 방법은 움직이는 피사체에 많은 비콘 장치를 부착해야한다. 이러한 제약사항을 극복하기 위해, 비콘장치가 없는 입력 비디오 영상으로부터 비정형 형상을 복원하는 연구가 멀티미디어 응용 분야에서 광범위하게 진행되고 있다. 이러한 관점에서 본 논문은 비정형 3D 형상을 복원할 수 있는 새로운 CPSRF(Chained Partial Stereo Rigid Factorization) 알고리즘을 제안한다. 본 방법은 스테레오 2D 비디오 영상으로부터 비정형 3D 형상을 프레임 별로 실시간 복원하는데 포커스 한다. 또한 시변 형상 변형은 가우시한 분포를 따라야 하는 제한을 두지 않는다. 실험결과에서는 제안한 CPSRF 방법의 복원 성능이 불규칙한 형상 변형을 고려하지 않은 기존 방법 보다 우수함을 확인한다.

• 대한전자공학회논문지SP
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• 제48권1호
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• pp.122-131
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• 2011

최근에 널리 사용되고 있는 단일 영상 기반의 3차원 얼굴 복원 방법인 변형 가능한 3차원 얼굴 형상 모델(3D morphable shape model)은 입력 영상으로부터 2차원 얼굴 특징점들을 정확하게 추출할 경우, 입력 얼굴과 유사한 3차원 얼굴 형상을 생성할 수 있다. 그러나 실시간 3차원 얼굴 복원 시스템과 같이 사용자의 협조가 불가능한 경우에는 자동으로 얼굴 특징점들을 추출해야 하기 때문에, 특징점 추출 오류가 발생하여 정확한 3차원 얼굴 형상을 생성하기 어려운 문제가 있다. 이러한 문제를 해결하기 위해서, 본 논문에서는 특징점 추출 시 오추출 특징점과 정추출 특징점을 자동으로 분류하고, 정추출 특징점들만을 이용하여 3차원 얼굴을 복원하는 방법을 제안하였다. 실험결과에서는 특징점 자동 추출 오류를 고려하지 않은 기존 방법과 비교한 결과, 제안방법의 3차원 얼굴 복원 성능이 크게 향상되었음을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3121-3142
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• 2017

We present a method for 3D shape reconstruction of inextensible deformable surfaces from a single image. The key of our approach is to represent the surface as a 3D triangulated mesh and formulate the reconstruction problem as a sequence of Linear Programming (LP) problems. The LP problem consists of data constraints which are 3D-to-2D keypoint correspondences and shape constraints which are designed to retain original lengths of mesh edges. We use a closed-form method to generate an initial structure, then refine this structure by solving the LP problem iteratively. Compared with previous methods, ours neither involves smoothness constraints nor temporal consistency, which enables us to recover shapes of surfaces with various deformations from a single image. The robustness and accuracy of our approach are evaluated quantitatively on synthetic data and qualitatively on real data.

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

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1634-1637
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• 2003

Any given object on the motor-driven turntable is pictured from 8 to 72 different views with a digital camera. 3D shape reconstruction is performed with the integrated software called by Scanware from these multiple digital photographs. There are several steps such as configuration, calibration, capturing, segmentation, shape creation, texturing and merging process during the shape reconstruction process. 3D geometry data can be exported to cad data such as Autocad input file. Also 3D image model is generated from 3D geometry and texture data, and is used to advertise the model in the internet environment. Consumers can see the object realistically from wanted views by rotating or zooming in the internet browsers with Scanbull spx plug-in. The spx format allows a compact saving of 3D objects to handle or download. There are many types of scan equipments such as laser scanners and photogrammetric scanners. Line or point scan methods by laser can generate precise 3D geometry but cannot obtain color textures in general. Reversely, 3D image modeling with photogrammetry can generate not only geometries but also textures from associated polygons. We got various 3D image models and introduced the process of getting 3D image model of an internet-connected watchdog robot.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.288-289
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• 2022

In this paper, we propose a method of obtaining high density geometric information using multi-view structured light. Reconstruction error due to the difference in resolution between the projector and the camera occurs when reconstruction a 3D shape from a structured light system to a single projector. This shows that the error in the point cloud in 3D is also the same when reconstruction the shape of the object. So we propose a high density method using multiple projectors to solve such a reconstruction error.

• 한국정밀공학회지
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• 제10권4호
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• pp.81-93
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• 1993

The three dimensional(3D) shape reconstruction from two dimensional(2D) cross-sections can be completed through three main phases : the input compilation, the triangular grid formation, and the smooth surface construction. In the input compilation phase, the cross-sections are analyzed to exctract the input data required for the shape reconstruction. This data includes the number of polygonized contours per cross-section and the vertices defining each polygonized contour. In the triangular grid formation phase, a triangular grid, leading to a polyhedral approximations, is constructed by extracting all the information concerning contour links between two adjacent cross- sections and then performing the appropriate triangulation procedure for each contour link. In the smooth surface construction phase, a smooth composite surface interpolating all vertices on the triangular grid is constructed. Both the smooth surface and the polyhedral approximation can be used as reconstructed models of the object. This paper proposes a new method for reconstructing the geometric model of a 3D objdect from a sequence of planar contours representing 2D cross-sections of the objdect. The method includes the triangular grid formation algorithms for contour closing, one-to-one branching, and one-to-many braanching, and many-to-many branching. The shape reconstruction method has been implemented on a SUN workstation in C.

• 제어로봇시스템학회논문지
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• 제21권5호
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• pp.459-464
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• 2015

An on-line quality control of hot steel products is one of the important issues in the steel industry because of cost minimization. In recent years, relative depth information of surface defects is increasingly required for strict quality control. In this paper, a 3D shape reconstruction scheme for defects on a hot steel surface based on a multi-spectral photometric stereo method is proposed. After simultaneously illuminating a hot steel surface by using vertical/horizontal linearly polarized lights of green and blue light sources, the corresponding 4 images are obtained. The photometric stereo method is then applied with the aid of a GPU (Graphic Processing Unit) to reconstruct the shape of the target surface based on these images. The proposed scheme was validated through experiments.

• 대한전자공학회논문지SP
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• 제44권4호통권316호
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• pp.1-7
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• 2007

본 논문은 정사투영 카메라로부터 얻어진 2차원 영상으로부터 복원된 3차원 형상과의 기하학적 관계를 분석한다 본 연구의 목적은 2차원과 3차원 관계를 기하학적으로 분석함으로서 잡음에 강인한 3차원 형상 복원에 기여하기 위함이다. 만약 3차원 형상 복원 시 특징점이 손실되지 않고 잡음이 존재하지 않는다면 3차원 형상복원은 고유치 행렬인수분해로 정확하게 얻을 수 있다. 그렇지만 실제 촬영된 피사체의 일부가 보이지 않는 오클루션 또는 낮은 해상도 등의 영향으로 인해, 피사체의 특징점 일부가 손실된 경우는 고유치 행렬인수분해의 계산적 문제가 발생되어 정확한 3차원 복원을 할 수 없게 된다. 더욱이 추출된 특징 점에 잡음이 포함될 경우는 복원된 3차원 형상 역시 그 섭동 영향을 받게 된다. 본 연구는 이러한 잡음환경에서도 손실된 특징 점을 정확히 유추하기 위해 2차원과 3차원 사이의 기하학적 특성을 분석하는데 포커스 한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.3-7
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• 2000

The authors have realized reconstruction of 3D shape using contacting method with pins and TCP/IP communication. In this paper, the working principal of the mechanism is proposed and tested. A special sensor system is designed as 148 matrix form to measure 3D shape. When contact occurs between pin and the plate of the sensor matrix, the position information of pins is sent to computer and raised height data of the pin is obtained by counter which accumlates encoder signal. So, all datum which contain 3-dimensional coordinate, is transferred using TCP/IP communication. Finally, 3D shape is reconstructured by Web browser of remote computer. The measuring result shows that the proposed mechanism is reliable and promising as a remote measuring device through Internet.