• Tunnel and Underground Space
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• v.22 no.2
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• pp.93-105
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• 2012

This paper compares the two- and three-dimensional (2D and 3D) approaches for the numerical determination of the equivalent mechanical properties of fractured rock masses. Both orthogonally-fractured model and discrete fracture networks (DFN) were used for the geometry and 2D models were cut in various directions from 3D model to compare their mechanical properties. Geological data were loosely based on the data available from Sellafield, UK. Analytical method based on compliance tensor transformation was used for investigation in orthogonally fractured rock and numerical experiments were conducted on fractured rock mass with DFN geometry. It is shown that 2D approach always overestimates the elastic modulus of fractured rock masses by a factor of up to around two because fractures are assumed to be perpendicular to the model plane in 2D problems. Poisson ratios tend to have larger values in 2D analysis while there is opposite trend in some sections. The study quantitatively demonstrates the limitation of the 2D approach that uses the simplified model from true 3D geometry.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.757-767
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• 2010

In this paper, we have studied the color compensation method for 3D that enables 3D color presentation similar to 2D. The color compensation method uses the difference of color presentation in 2D and 3D mode. First, the RGB I/O relationship curve was derived in 2D and 3D mode based on the input RGB color bar images. The relationship was modeled in modified power-law forms. Based on the modeling information, we generated color mapping tables, which can be used for compensating the difference of colors. The proposed color mapping block can be added at the output block of a 3DTV system, where the 2D content can be bypassed but the 3D content RGB data can be processed using the color mapping table. The experimental results show that the proposed method improves color presentation of a 3DTV system using a proper color compensation based on 2D presentation.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.161-169
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• 2012

In general, Euclidean minimum spanning tree is a tree connecting input nodes with minimum connecting cost. But the tree may not be optimal when applied to real world problems of three dimension. In this paper, three dimension Euclidean minimum spanning tree is proposed, connecting all input nodes of 3-dimensional space with minimum cost. In experiments for 30,000 input nodes with 100% space ratio, the tree produced by the proposed method can reduce 90.0% connection cost tree, compared with the tree by two dimension Prim's minimum spanning tree. In two dimension plane, the proposed tree increases 251.2% connecting cost, which is pointless in 3-dimensional real world. Therefore, the proposed method can work well for many connecting problems in real world space of three dimensions.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.211-220
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• 2003

As Geographic Information Systems represent three dimensional topological information, The Systems provide accurate and delicate services for users. In order to execute three dimensional topological operations, a dimensional transformation and heterogeneous spatial models should be used. However, the existing systems that use the dimensional transformation and the heterogeneous models, is not only difficult to operate the spatial operators, but also happened to support non-interoperability. Therefore, in order to solve the problems, we proposed three dimensional spatial object models that supported two dimensional object models and implemented them to show validity of the proposed models. When designing the three dimensional topological operators, we used 3DE-9IM which extended DE-9IM to support three dimensional concepts, and implemented operators on the component environment with object oriented concepts. The proposed three dimensional spatial object models and topological operators can support interoperability between systems, and execute spatial queries efficiently on three dimensional spatial objects.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.55-61
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• 2007

In this paper, we propose a three-dimensional(3D) active shape models for medical image segmentation. In order to build a 3D shape model, we need to generate a point distribution model(PDM) and select corresponding landmarks in all the training shapes. The manual determination method, two-dimensional(2D) method, and limited 3D method of landmark correspondences are time-consuming, tedious, and error-prone. In this paper, we generate a 3D statistical shape model using the 3D model generation method of a distance transform and a tetrahedron method for landmarking. After generating the 3D model, we extend the shape model training and gray-level model training of 2D active shape models(ASMs) and we use the integrated modeling process with scale and gray-level models for the appearance profile to represent the local structure. Experimental results are comparable to those of region-based, contour-based methods, and 2D ASMs.

• Smart Media Journal
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• v.3 no.4
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• pp.22-27
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• 2014

Three-dimensional image reconstruction allows us to represent real objects in the virtual space and observe the objects at arbitrary view points. This technique can be used in various application areas such as education, culture, and art. In this paper, we propose an implementation method of the high-quality three-dimensional object using multiple Kinect cameras released from Microsoft. First, We acquire color and depth images from triple Kinect cameras; Kinect cameras are placed in front of the object as a convergence form. Because original depth image includes some areas where have no depth values, we employ joint bilateral filter to refine these areas. In addition to the depth image problem, there is an color mismatch problem in color images of multiview system. In order to solve it, we exploit an color correction method using three-dimensional geometry. Through the experimental results, we found that three-dimensional object which is used the proposed method is more naturally represented than the original three-dimensional object in terms of the color and shape.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2157-2163
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• 2011

In this paper, we designed 2D, 2.5D cloth design system and a 3D cloth animation system. They make the 3D cloth animation possible by using coordinate points extracted from 2D and 2.5D cloth design system in order to realize a system that allows customers to wear clothes in the virtual space. To make natural draping, it uses for description the mesh creation and transformation algorithms, path extraction algorithm, warp algorithm, and brightness extraction and application algorithms. The coordinate points extracted here are received as text format data and inputted as clothing information in the cloth file. Moreover, the cloth file has a 2D pattern and is realized to be used in the 3D cloth animation system. The 3D cloth animation system generated in this way builds a web-based fashion mall using ISB (Internet Space Builder) and lets customers view the clothing animation on the web by adding the animation process to the simulation result.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.67-67
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• 2010

과학교육에서 효과적인 과학 수업을 위하여 과학사 도입의 중요성이 계속 강조되어 왔다. 이에 따라 과학 교과서에는 많은 과학사 자료가 사용되고 있다. 하지만 과학 교과서에 사용된 과학사 자료가 어떤 유형과 맥락에서 어떠한 역할을 하고 있는 지에 대한 면밀한 분석은 이루어지지 못한 실정이다. 이에 본 연구에서는 선행 연구와 관련 문헌 분석을 통해 과학 교과서에 사용된 과학사 자료를 분석하기 위한 3차원 틀을 개발하고, 이를 제 7차 교육과정의 과학 교과서 지구과학 내용을 대상으로 적용하였다. 개발된 분석틀은 수업맥락, 역할, 제시유형의 3개 차원으로 구성된다. 수업맥락 차원은 흥미, 사회-문화적, 인식론적, 개념적 맥락의 4가지 영역으로 세분되며, 제시유형 차원은 에피소드/일화, 발견/고안, 선형적인 발전, 역사적 실험의 4가지 영역으로 세분된다. 역할 차원은 기본적, 보충적, 탐구적의 3가지 영역으로 세분된다. 개발된 3차원 분석틀을 적용하여 과학 교과서의 지구과학사 자료들을 분석한 결과, 수업맥락 차원에서는 개념적 맥락의 과학사 자료가 모든 학년별 과학 교과서에서 가장 많았다. 역할 차원에서는 기본적 역할이 압도적으로 많았으며, 탐구적 역할의 경우에는 매우 적었다. 제시유형 차원에서는 발견/고안과 선형적인 발전 유형이 대부분이었고, 에피소드/일화 유형의 자료는 주로 흥미 맥락과 연계되어 극히 일부만 사용되고 있었다. 3차원 각 영역들을 48개의 조합으로 분석한 결과, '개념적 수업맥락-기본적 역할-발견/고안 유형'과 '개념적 수업맥락-기본적 역할-선형적 발전 유형' 2개 조합에 집중되었으며, 나머지 조합들의 빈도는 매우 낮았다. 전체적으로 3차원 분석틀 각 영역에 부합하는 과학사 자료가 과학 교과서에 다양하게 포함되지 못하고 일부 영역에만 집중되는 것으로 나타났으며, 이러한 연구 결과는 앞으로 다양한 수업맥락, 역할, 그리고 유형으로 과학사 자료들이 개발될 필요가 있음을 시사한다.

• The KIPS Transactions:PartB
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• v.18B no.1
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• pp.21-28
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• 2011

A 3D face shape derived from 2D images may be useful in many applications, such as face recognition, face synthesis and human computer interaction. To do this, we develop a fast 3D Active Appearance Model (3D-AAM) method using depth estimation. The training images include specific 3D face poses which are extremely different from one another. The landmark's depth information of landmarks is estimated from the training image sequence by using the approximated Jacobian matrix. It is added at the test phase to deal with the 3D pose variations of the input face. Our experimental results show that the proposed method can efficiently fit the face shape, including the variations of facial expressions and 3D pose variations, better than the typical AAM, and can estimate accurate 3D face shape from images.

• Journal of Broadcast Engineering
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• v.26 no.1
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• pp.70-78
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• 2021

Estimating 3D information from a single image is one of the essential problems in numerous applications. Since a 2D image inherently might originate from an infinite number of different 3D scenes, thus 3D reconstruction from a single image is notoriously challenging. This challenge has been overcame by the advent of recent deep convolutional neural networks (CNNs), by modeling the mapping function between 2D image and 3D information. However, to train such deep CNNs, a massive training data is demanded, but such data is difficult to achieve or even impossible to build. Recent trends thus aim to present deep learning techniques that can be trained in a weakly-supervised manner, with a meta-data without relying on the ground-truth depth data. In this article, we introduce recent developments of weakly-supervised deep learning technique, especially categorized as scene 3D reconstruction and object 3D reconstruction, and discuss limitations and further directions.