• 도시과학
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• 제7권2호
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• pp.53-60
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• 2018

Digital Twin is a technology that creates a photocopy of real-world objects on a computer and analyzes the past and present operational status by fusing the structure, context, and operation of various physical systems with property information, and predicts the future society's countermeasures. In particular, 3D rendering technology (UAS, LiDAR, GNSS, etc.) is a core technology in digital twin. so, the research and application are actively performed in the industry in recent years. However, UAS (Unmanned Aerial System) and LiDAR (Light Detection And Ranging) have to be solved by compensating blind spot which is not reconstructed according to the object shape. In addition, the terrestrial LiDAR can acquire the point cloud of the object more precisely and quickly at a short distance, but a blind spot is generated at the upper part of the object, thereby imposing restrictions on the forward digital twin modeling. The UAS is capable of modeling a specific range of objects with high accuracy by using high resolution images at low altitudes, and has the advantage of generating a high density point group based on SfM (Structure-from-Motion) image analysis technology. However, It is relatively far from the target LiDAR than the terrestrial LiDAR, and it takes time to analyze the image. In particular, it is necessary to reduce the accuracy of the side part and compensate the blind spot. By re-optimizing it after fusion with UAS and Terrestrial LiDAR, the residual error of each modeling method was compensated and the mutual correction result was obtained. The accuracy of fusion-based 3D model is less than 1cm and it is expected to be useful for digital twin construction.

• International Journal of Computer Science & Network Security
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• 제22권11호
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• pp.71-76
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• 2022

The article aims to consider the role of computer technologies in contemporary jewelry art. The importance of computer programming, 3D-modeling and 3D-printing for the process of jewelry creating, its advertising and sales is emphasized. Both the positive features of the possibility of using computer technologies in jewelry and their shortcomings are considered. The process of changing the nature of jewelry design after the start of the use of digital technologies is highlighted. The issue of changing the perception and evaluation of a work of jewelry art, the creation of which uses mechanization, has been updated.

• 한국BIM학회 논문집
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• 제6권4호
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• pp.27-34
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• 2016

A Building Information Model (BIM) is an attempt to simulate the process of building structures in a three-dimensional (3D) digital space. While the technology is usually applied to structured buildings, bridges, and underground facilities, it is rarely applied to an unstructured environment of earthwork operations. If a BIM is used for earthworks, the 3D simulation can be used for construction equipment guidance and earthwork management. This paper presents a real-time, 3D earthwork BIM that provides a 3D graphical simulation of excavators in conjunction with geographic modeling. Developing a real-time, 3D earthwork BIM requires handling a variety of factors, such as geographical information and vehicular movement. This paper mainly focuses on the management of these attributes and provides a database design for storing and retrieving data. In an example application, a prototype of the 3D earthwork BIM is presented to understand what it would provide when used during earthwork operations at a construction site.

• International Journal of CAD/CAM
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• 제9권1호
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• pp.93-102
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• 2010

Shaping realistic hairstyles for digital characters is a difficult, long and tedious task. The lack of appropriate interaction metaphors enabling efficient and simple, yet accurate hair modeling further aggravates the situation. This paper presents 3D interaction metaphors for modeling virtual hair using haptic interfaces. We discuss user tasks, ergonomic aspects, as well as haptics-based styling and fine-tuning tools on an experimental prototype. In order to achieve faster haptic rates with respect to the hair simulation and obtain a transparent rendering, we adapt our simulation models to comply with the specific requirements of haptic hairstyling actions and decouple the simulation of the hair strand dynamics from the haptic rendering while relying on the same physiochemical hair constants. Besides the direct use of the discussed interaction metaphors in the 3D modeling area, the presented results have further application potential in hair modeling facilities for the entertainment industry and the cosmetic sciences.

• 디지털콘텐츠학회 논문지
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• 제15권4호
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• pp.521-526
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• 2014

본 논문은 3차원 모델링을 위한 두 개의 3차원 데이터들을 정합하는데 있어서 효율적인 방법을 제안한다. 3차원 데이터들은 서로 임의의 각도에서 취득한 것으로 취득 장치의 위치 및 2차원 영상정보가 포함 되어있다. 이 정보들을 이용하여 보다 빠르고 정확한 정합을 이루는 방법을 제안한다. 2차원 영상정보를 이용하여 보다 쉽게 대응점들을 찾아내는 것으로 대응하는 4개의 점에 대한 체적을 이용하여 모형의 크기를 일치시킨다. 또한, 이 점들로부터 얻어낸 좌표축의 호모그라피(homography)를 추출해냄으로써 2개의 데이터에 대한 정합과정은 보다 빠르고 정확하게 이루어진다. 제안한 알고리즘의 장점은 2차원 영상정보를 이용하기 때문에 정합하는 데에 있어서 오류가 적고 반복하는 과정이 불필요하다. 또한, 취득된 2차원 영상정보를 정합하고, 이를 3차원 모형에 2차원 영상을 씌움으로써 정합은 완벽하게 이루어진다.

• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.214-222
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• 2012

The shipbuilding process is changing due to changes in the development environment and technological requirements for military ships. This would also hold true for a submarine, because its shipbuilding process includes complicated design and construction conditions. System improvement efforts for the design and construction of military ships have continued with the goal of overcoming these conditions. At present, the Korea Navy is developing a 3,000 ton-class Korean type submarine, and its design is progressing by the introduction of a full 3D-ship CAD system. Although the 3D modeling system was introduced for effective design realization through the introduction of collaborative design and active utilization of M&S (modeling and simulation), the introduction effects are not yet generally obvious, according to the characteristics of ship design. The present paper discusses the collaborative environment for developing a submarine to enhance this. This paper proposes the architecture and data structure of a system for realizing collaborative design and discusses a case system developed on the basis of this.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.719-722
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• 2003

This paper describes a novel experiment that measures the skin movement of a hand based on MR (magnetic resonance) images in conjunction with surface modeling techniques. The proposed approach consists of 3 phases: (1) MR scanning of a hand with surface makers, (2) 3D reconstruction from the MR images. and (3) registration of the 3D models. The results of registration are used to trace the skin movement with respect to underlying bone motions by measuring the positions of the surface markers.

• 한국정밀공학회지
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• 제21권8호
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• pp.164-170
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• 2004

The skin movement artifacts are referred to as the relative motion of skin with respect to the motion of underlying bones. This is of great importance in joint biomechanics or internal kinematics of human body. This paper describes a novel experiment that measures the skin movement of a hand based on MR(magnetic resonance) images in conjunction with surface modeling techniques. The proposed approach consists of 3 phases: (1) MR scanning of a hand with surface makers, (2) 3D reconstruction from the MR images, and (3) registration of the 3D models. The MR images of the hand are captured by 3 different postures. And the surface makers which are attached to the skin are employed to trace the skin motion. After reconstruction of 3D models from the scanned MR images, the global registration is applied to the 3D models based on the particular bone shape of different postures. The results of registration are then used to trace the skin movement by measuring the positions of the surface markers.

• 대한공간정보학회지
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• 제13권3호
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• pp.25-32
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• 2005

본 논문은 LIDAR 데이터와 수치지도를 이용한 점 기반의 3차원 건물모델링 방법을 제안하는데 목적이 있다. 본 논문에서 제안한 방법은 크게 건물점 추출, 지붕유형 분류, 지붕유형별 3차원 모델링 단계로 나뉜다. 먼저 수치지도의 건물 외곽선과 LIDAR 데이터를 중첩시켜 건물폴리곤 내에 있는 LIDAR 점들 중에서 지면과 벽면 및 수목을 제거하여 건물의 지붕점만을 추출한다. 추출된 건물 지붕점들은 ODR(Orthogonal Distance Regression) 방법을 통해 평면근사하여 점들이 평면상의 점이면 평면형(flat) 지붕으로 분류하고 그렇지 않으면 박공형(gable)과 원통형(arch)으로 근사한 후 평균제곱근오차가 작은 쪽으로 지붕유형을 결정한다. 실험결과 본 연구에서 제안한 방법은 3가지 유형의 단순 지붕유형을 성공적으로 분류하였으며, LiDAR 데이터와 수치지도를 이용한 자동 3차원 건물모델링의 가능성을 제시하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.516-516
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• 2002

With the wide usage of LiDAR data and high-resolution satellite image, 3D modeling of buildings in urban areas has become an important research topic in the photogrammetry and computer vision field for many years. However the previous modeling has its limitations of merely texturing the image to the DSM surface of the study area and does not represent the relief of building surfaces. This study is focused on presenting a system of realistic 3D building modeling from consecutive stereo image sequences using digital camera. Generally when acquiring images through camera, various parameters such as zooming, focus, and attitude are necessary to extract accurate results, which in certain cases, some parameters have to be rectified. It is, however, not always possible or practical to precisely estimate or rectify the information of camera positions or attitudes. In this research, we constructed the collinearity condition of stereo images through extracting the distinctive points from stereo image sequence. In addition, we executed image matching with Graph Cut method, which has a very high accuracy. This system successfully performed the realistic modeling of building with a good visual quality. From the study, we concluded that 3D building modeling of city area could be acquired more realistically.