• Journal of the Korea Computer Graphics Society
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• v.21 no.2
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• pp.1-10
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• 2015

In this paper, we propose an improved surface reconstruction method from an oriented point cloud. Our method is a classical least-square scheme, but is based on the 7-direction box-spline and the BCC (Body-Centered Cubic) lattice, which results in surfaces with superior quality and lower computational overhead, compared to other methods based on the B-splines on the Cartesian lattice. Specifically, when compared with two of the most popular techniques our method results in better surfaces but only takes ${\approx}53%$ computation time.

• Architectural research
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• v.21 no.4
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• pp.111-116
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• 2019

The premise of this research is the recent advancement of Building Information Modeling(BIM) Technology and Laser Scanning Technology(3D Scanning). The purpose of the paper is to amplify the potential offered by the combination of BIM and Point Cloud Data (PCD) for structural analysis. Today, enormous amounts of construction site data can be potentially categorized and quantified through BIM software. One of the extraordinary strengths of BIM software comes from its collaborative feature, which can combine different sources of data and knowledge. There are vastly different ways to obtain multiple construction site data, and 3D scanning is one of the effective ways to collect close-to-reality construction site data. The objective of this paper is to emphasize the prospects of pre-scanning and post-scanning automation algorithms. The research aims to stimulate the recent development of 3D scanning and BIM technology to develop Scan-to-BIM. The paper will review the current issues of Scan-to-BIM tasks to achieve As-Built BIM and suggest how it can be improved. This paper will propose a method of coordinating and utilizing PCD for construction and structural analysis during construction.

• Tunnel and Underground Space
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• v.21 no.6
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• pp.439-449
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• 2011

The characteristics of rock fractures for engineering rock classification are investigated by analyzing three dimensional point cloud generated from adjusted digital images of a tunnel face during construction and the tunnel is reinforced based on the supporting pattern suggested by the RMR and the Q system using parameters extracted from those images. As results, it is possible saving time required from face mapping to tunnel reinforcing work, enhancing safety during face mapping work in tunnels and reliability of both the mapping information and selecting supporting pattern by storing the files of digital images and related information which can be checked again, if necessary sometime in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.2
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• pp.179-186
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• 2004

This study describes that the method of precision measurement of vehicle shape and the method of measurement the deformation that it is occurred the reason of accident using industrial photogrammatry. The curved shape is measured using the projection target which is able to acquire the point cloud data. 3D coordinates of the target were able to acquire through object picturing and analysis of coordinates. The acquired point cloud data was done 3D modeling to form the surface with TIN. Also, It able to interpretate a deformation surveying accurately the occurred parts of deformation, then can furnish to the analysis of traffic accident the precise and effective data.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.633-641
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• 2015

In this study, we proposed a three-dimensional (3D) scanning system based on laser-vision technique and rotary mechanism for automatic 3D model reconstruction. The proposed scanning system consists of a laser projector, a camera, and a turntable. For laser-camera calibration a new and simple method was proposed. 3D point cloud data of the surface of scanned object was fully collected by integrating extracted laser profiles, which were extracted from laser stripe images, corresponding to rotary angles of the rotary mechanism. The obscured laser profile problem was also solved by adding an addition camera at another viewpoint. From collected 3D point cloud data, the 3D model of the scanned object was reconstructed based on facet-representation. The reconstructed 3D models showed effectiveness and the applicability of the proposed 3D scanning system to 3D model-based applications.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.257-265
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• 2010

This study concerned about "Gemini type co-surfactant" which has very interesting properties with new components. They were synthesized by reaction of diethylene glycol monoethyl ether and dicarboxylic acid. The structure could be comfirmed with FT-IR and $^1H$-NMR. Surface active properties such as surface tension, evaluated cmc, cloud point, emulsing power were measured respectively at given conditions. Their surface tensions in the aqueous solution were decreased to 33~35 dyne/cm, which was lower than 39 dyne/cm of SDS, and their cmc values evaluated by surface tension method were $5.0{\times}10^{-1}\sim7.5{\times}10^{-1}$ mol/L. And the emulsifying power was excellent in jojoba oil. All of the synthesized Gemini surfactants possessed good water solubility and their cloud point were $48\sim58^{\circ}C$. As results, Gemini surfactants which were synthesized are expected to be applied as O/W emulsifiers.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.765-774
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• 2019

In this paper, we propose a point cloud matching algorithm for multiple RGB-D cameras. In general, computer vision is concerned with the problem of precisely estimating camera position. Existing 3D model generation methods require a large number of cameras or expensive 3D cameras. In addition, the conventional method of obtaining the camera external parameters through the two-dimensional image has a large estimation error. In this paper, we propose a method to obtain coordinate transformation parameters with an error within a valid range by using depth image and function optimization method to generate omni-directional three-dimensional model using 8 low-cost RGB-D cameras.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.157-159
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• 2019

Hologram technology has been actively developed in terms of generation, transmission, and reproduction of 3D objects, but it is currently in a state of rest because of various limitations. Beyond VR and AR, the pseudo-hologram market is growing at an intermediate stage to meet the needs of new technologies. The key to the technology of hologram is to generate vast 3 dimensional data in the form of a point cloud, transmit the vast amount of data through the communication network in real time, and reproduce it like the original at the destination. In this paper, we propose a method to transmit massive 3 - D data in real - time and transmit the minutiae points of 3 - dimensional object information to reproduce the object as similar to original.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.147-150
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• 2021

최근 컴퓨터 그래픽 기술이 발전함에 따라 가상으로 만들어낸 객체와 현실 객체 사이의 분간이 어려워지고 있으며, AR/VR/XR 등의 서비스를 위해 현실 객체를 컴퓨터 그래픽으로 표현하는 기술의 연구가 활발히 진행되고 있다. 포인트 클라우드는 현실 객체를 표현하는 기술 중의 하나로 객체의 표면을 수많은 3차원의 점으로 표현하며, 2차원 영상보다 더욱 거대한 데이터 크기를 가지게 된다. 이를 다양한 서비스에 응용하기 위해서는 3차원 데이터의 특징에 맞는 고효율의 압축 기술이 필요하며, 국제표준기구인 MPEG에서는 연속적인 움직임을 가지는 동적 포인트 클라우드를 2차원 평면으로 투영하여 비디오 코덱을 사용해 압축하는 Video-based Point Cloud Compression (V-PCC) 기술이 연구되고 있다. 포인트 클라우드를 2차원 평면에 투영하는 방식은 점유 맵 (Occupancy Map), 기하 영상 (Geometry Image), 속성 영상 (Attribute Image) 등의 2차원 정보와 보조 정보를 사용해 압축을 진행하고, 부호화 과정에서는 보조 정보와 2차원 영상들의 정보를 사용해 3차원 포인트 클라우드를 재구성한다. 2차원 영상을 사용해 포인트 클라우드를 생성하는 특징 때문에 압축 과정에서 발생하는 영상 정보의 열화는 포인트 클라우드의 품질에 영향을 미친다. 이와 마찬가지로 추가적인 기술을 사용한 2차원 영상 정보의 향상으로 포인트 클라우드의 품질을 향상할 수 있을 것으로 예상된다. 이에 본 논문은 V-PCC 기술에서 생성되는 영상 정보에 2차원 보간 (Interpolation) 기술을 적용하여 기존의 영상 정보에 포함되지 않은 추가적인 포인트를 생성하는 것으로 재구성되는 포인트 클라우드의 밀도를 증가시키고 그 영향을 분석하고자 한다.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.487-495
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• 2023

This paper presents a method for autonomous exploration of indoor environments using a 2-dimensional Light Detection And Ranging (LiDAR) scanner. The proposed frontier-based exploration method considers navigability from the current robot position to extracted frontier targets. An approach to constructing the point cloud grid map that accurately reflects the occupancy probability of glass obstacles is proposed, enabling identification of safe frontier grids on the safety grid map calculated from the point cloud grid map. Navigability, indicating whether the robot can successfully navigate to each frontier target, is calculated by applying the skeletonization-informed rapidly exploring random tree algorithm to the safety grid map. While conventional exploration approaches have focused on frontier detection and target position/direction decision, the proposed method discusses a safe navigation approach for the overall exploration process until the completion of mapping. Real-world experiments have been conducted to verify that the proposed method leads the robot to avoid glass obstacles and safely navigate the entire environment, constructing the point cloud map and calculating the navigability with low computing time deviation.