• 한국정밀공학회지
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• 제21권4호
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• pp.57-63
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• 2004

This paper describes a method for digitizing the compound surfaces which are comprised of several unknown feature shapes such as base surface, and draft wall. From the reverse engineering's point of view, the main step is to digitize or gather three-dimensional points on an object rapidly and precisely. As well known, the non-contact digitizing apparatus using a laser or structured light can rapidly obtain a great bulk of digitized points, while the touch or scanning probe gives higher accuracy by directly contacting its stylus onto the part surface. By combining those two methods, unknown features can be digitized efficiently. The paper proposes a digitizing methodology using the approximated surface model obtained from laser-scanned data, followed by the use of a scanning probe. Each surface boundary curve and the confining area is investigated to select the most suitable digitizing path topology, which is similar to generating NC tool-paths. The methodology was tested with a simple physical model whose shape is comprised of a base surface, draft walls and cavity volumes.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.17-18
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• 2015

In manufacturing industry, image scanning technique has made enormous progress in past decades. 3D models have been also very important to continuously monitor the related spatial information for freeform buildings. The process of shape making of 3D scanning is as follows: mesh surface segmentation, NURBS surface generation, and parametric solid model generation. We will review the process and applying process. Especially in the construction industry, 3D data collection by laser scanning has become an high quality 3D models. Therefore, in this research, we have an effort to review construction of reverse design process for freeform envelope using 3D scanning. The technology enables many 3D shape engineering and design parameterization of reverse engineering in the construction site.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.76-78
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• 2005

When the data from the artificial satellite is analyzed, recent years it is perceived to vegetation index using BRF(Bidirectional Reflectance Factor) of the observation target. To make the BRF models, it is important to measure the 3D structure of the observation target actually. In this study, it is proposed to the observation technique by using laser scanning data. Also, our team has been operating the radio controlled helicopter which can fly over the tall forest canopy and it can be equipped the measurement system.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.451-454
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• 2007

There is an inseparable relation between human race and engineering work. As world developed into highly industrialized society, a diversity of large structures is being built up correspondently to limited topographical circumstance. Though large structures are national establishments which provide us with convenience of life, there are some disastrous possibilities which were never predicted such as ground subsidence and degradation. It is very difficult to analyze the volume of total metamorphosis with the relative displacement measurement system which is now used and it is impossible to know whether there is structural metamorphosis within a permissible range of design or not. In this research with an object of 13-year-old earthen dam, through generating point-cloud which has 3D spatial coordinates(x, y, z) of this dam by means of 3D Laser Scanning, we can get real configuration data of slanting surface of this dam with this method of getting a number of 3D spatial coordinates(x, y, z). It gives 3D spatial model to us and we can get various information of this dam such as the distance of slanting surface of dam, dimensions and cubic volume. It can be made full use of as important source material of reinforcement and maintenance works to detect previously the bulging of the dam through this research.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.711-719
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• 2006

In this study, a 3D laser scanner is applied to evaluate of the stability of rock slope and to establish a adequate counter-method. From 3D scanning results, three dimensional digital data of rock slope is acquired, and then it is investigated for the engineering properties of discontinuities in rock mass. On the base of the result, we carry out the analysis of slope stability using the methods of the stereographic projection. In particular, the use of a 3D laser scanner is powerful about the slope on which person is difficult to approach because we can obtain the informations of discontinuities from the 3D digital data.

• 한국측량학회지
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• 제27권3호
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• pp.347-356
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• 2009

최근 산업계를 비롯한 다양한 분야에서 대상물에 대한 3차원 측정과 형상화에 대한 요구가 급증함에 따라 측정 및 3차원 모델링을 위한 3차원 레이저스캐닝 시스템의 활용이 급증하고 있다. 그러나 3차원 레이저 스캐닝 시스템의 역할 및 활용의 증가하고 있는데 반해 스캔에 의해 획득되는 결과에는 다양한 원인에 의한 오차가 포함됨으로 인하여 고정밀 측정이 요구되는 분야에서 활용에 부분적인 제약으로 작용하고 있다. 이에 본 연구에서는 레이저측정방식을 채용하고 있는 3차원 레이저스캐닝 시스템을 이용하여 오차발생의 가장 큰 요인으로 조사되고 있는 측정대상을 표면물질의 반사율에 따른 오차발생특성과 발생비율을 분석함으로써 3차원 스캔자료의 정확도 향상을 꾀하고자 하였다. 연구결과, 측정대상물의 표면물질에 따라 반사량이 다르게 나타남을 확인할 수 있었으며, 표면반사율과 레이저파의 반사량 사이에 비례관계가 성립되는 특성을 확인할 수 있었다.

• 한국측량학회지
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• 제30권2호
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• pp.135-142
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• 2012

본 연구에서는 대용량 항공 레이저 스캐닝 자료로부터 DSM(Digital Surface Model) 및 DTM(Digital Terrain Model)을 효율적으로 생성하기 위하여 다중 코어 피씨클러스터(PC-Cluster)에 기반한 병렬처리방식을 제안하였다. 이를 위하여 MPI(message passing interface)만을 사용하는 기존 MPI 모델을 변형하여 MPI와 OpenMP를 병용한 하이브리드(hybrid) 모델을 제작하였으며 다중 코어 피씨클러스터에서 그 성능을 평가하였다. 결과적으로, 하이브리드 모델과 기존 모델을 비교하였을 때 DSM을 생성하기 위한 보간에서는 다소 불리하지만 MPI 호출을 줄임으로써 전반적인 성능을 향상시킬 수 있었다. 아울러, 불규칙한 항공 레이저 스캐닝 자료의 분포로부터 발생하는 코어간 부하 불일치를 OpenMP의scheduling 기능을 통해 조절함으로써 하이브리드 모델의 성능을 향상시킬 수 있었다.

• 한국정밀공학회지
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• 제20권9호
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• pp.197-204
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• 2003

This study proposes a method to reduce errors in scanning object and registration using a laser scanner. The method consists of 3 stages. First, there is an error induced by the difference of the distance between the probe and the object. It is possible to reduce the error by planning a scanning strategy: object setting, scan path. Second, the scan data of the tooling ball affects calculating the tooling ball center. A z-direction compensation is given to calculate more accurate registration points. Third, three points are used to determine a coordinate transformation on each frame. The maximum error usually lies on the third tooling ball in the conventional merging method. LSM (Least Square Method) is applied to a coordinate transformation to reduce the registration error.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.1193-1198
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• 2005

The pre-assembly takes a large portion of the fabrication cost of steel bridges. In order to save the fabrication cost through the improvement of the conventional pre-assembling process, this research investigates a numerical pre-assembly simulation as an alternative to current pre-assembling process. The 3D laser scanning was utilized in site and measuring data for steel box were analyzed. The productivity of pre-assembly simulation system is compared with the conventional pre-assembling system. This paper identifies feasibility on the alternative pre-assembling process and then proposes the scheme of the pre-assembly simulation system development satisfying the current pre-assembly inspection of standards.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.530-535
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• 2002

An approach for quickly updating GIS building data using high resolution remotely sensed data is proposed in this paper. High resolution remotely sensed data could be aerial photographs, satellite images and airborne laser scanning data. Data from different types of sensors are integrated in building extraction. Based on the extracted buildings and the outdated GIS database, the change-detection-template can be automatically created. Then, GIS building data can be fast updated by semiautomatically processing the change-detection-temp late. It is demonstrated that this approach is quick, effective and applicable.