• 한국측량학회지
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• 제36권5호
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• pp.319-333
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• 2018

As human beings spend more time indoors, and with the growing complexity of indoor spaces, more focus is given to indoor spatial applications and services. 3D topological networks are used for various spatial applications that involve navigation indoors such as emergency evacuation, indoor positioning, and visualization. Manually generating indoor network data is impractical and prone to errors, yet current methods in automation need expensive sensors or datasets that are difficult and expensive to obtain and process. In this research, a methodology for semi-automatically generating a 3D indoor topological model based on IndoorGML (Indoor Geographic Markup Language) is proposed. The concept of Shooting Point is defined to accommodate the usage of omnidirectional images in generating IndoorGML data. Omnidirectional images were captured at selected Shooting Points in the building using a fisheye camera lens and rotator and indoor spaces are then identified using image processing implemented in Python. Relative positions of spaces obtained from CAD (Computer-Assisted Drawing) were used to generate 3D node-relation graphs representing adjacency, connectivity, and accessibility in the study area. Subspacing is performed to more accurately depict large indoor spaces and actual pedestrian movement. Since the images provide very realistic visualization, the topological relationships were used to link them to produce an indoor virtual tour.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.508-511
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• 2006

Generally, stereo pair images are necessary for 3D viewing. In the absence of quality stereo-pair images, it is possible to synthesize a stereo-mate suitable for 3D viewing with a single image and a depth-map. In remote sensing, DEM is usually used as a depth-map. In this paper, LiDAR data was used instead of DEM to make a stereo pair from a single aerial photo. Each LiDAR point was assigned a brightness value from the original single image by registration of the image and LiDAR data. And then, imaginary exposure station and image plane were assumed. Finally, LiDAR points with already-assigned brightness values were back-projected to the imaginary plane for synthesis of a stereo-mate. The imaginary exposure station and image plane were determined to have only a horizontal shift from the original image's exposure station and plane. As a result, the stereo-mate synthesized in this paper fulfilled epipolar geometry and yielded easily-perceivable 3D viewing effect together with the original image. The 3D viewing effect was tested with anaglyph at the end.

• 한국지리정보학회지
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• 제20권1호
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• pp.152-161
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• 2017

모바일 매핑 시스템(Mobile Mapping System: MMS) 센서를 이용한 3차원 정밀지도의 구축은 자율주행 자동차 개발에 필요한 기술이다. 본 논문은 MMS LiDAR(Light Detection And Ranging) 센서를 이용하여 획득한 점군자료를 이용하여 도로주변의 3차원 객체 추출에 관한 연구를 수행하였다. 우선, MMS LiDAR 점군자료 이용하여 수치표면모형(DSM: Digital Surface Model)을 제작하고, 생성된 DSM을 기반으로 경사도 지도를 제작하였다. 추출된 경사도 정보를 이용하여 도로주변의 3차원 객체를 식별하였고, 모폴로지 필터링 기법을 이용하여 도로주변의 3차원 객체 중 총 97%의 객체를 추출하였다. 본 연구는 MMS 센서를 이용하여 획득한 공간정보자료를 기반으로 도로 주변의 3차원 객체를 추출함으로써 최근 주목받고 있는 자율주행기술의 활용성에 관한 방안을 제시하였다는데 의의가 있다.

• 한국가스학회지
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• 제12권3호
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• pp.50-55
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• 2008

본 연구에서는 ethylbenzene+n-butanol 및 ethylbenzene+n-hexanol 계의 인화점을 Tag 개방식 장치(ASTM D1310-86)를 이용하여 측정하였다. 이성분계 혼합물은 "최소인화점 현상"(minimun flash point behavior)을 보였다. 실험값은 Raoult의 법칙, UNIQUAC 모델식과 NRTL 모델식에 의해 계산된 값들과 비교 하였다. 그 결과, UNIQUAC 모델식과 NRTL 모델식에 의한 예측값이 Rauolt의 법칙에 의한 예측값보다 실험값에 더욱 근접하였다. 이는 ethylbenzene+n-butanol 및 ethylbenzene+n-hexanol 계와 같은 비이상 용액의 활동도 계수값을, UNIQUAC 및 NRTL 모델식이 Raoult의 법칙보다 정확하게 계산하기 때문이다. 또한, NRTL 모델식의 실험값에 대한 모사성이 UNIQUAC 모델식의 그것 보다 우수하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1137-1139
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• 2003

This paper proposed a practical method for building detection and extraction using airborne laser scanning data. The proposed method consists mainly of two processes: low and high level processes. The major distinction from the previous approaches is that we introduce a concept of pseudogrid (or binning) into raw laser scanning data to avoid the loss of information and accuracy due to interpolation as well as to define the adjacency of neighboring laser point data and to speed up the processing time. The approach begins with pseudo-grid generation, noise removal, segmentation, grouping for building detection, linearization and simplification of building boundary , and building extraction in 3D vector format. To achieve the efficient processing, each step changes the domain of input data such as point and pseudo-grid accordingly. The experimental results shows that the proposed method is promising.

• 한국측량학회지
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• 제37권5호
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• pp.359-366
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• 2019

Indoor spatial data has great importance as the demand for representing the complex urban environment in the context of providing LBS (Location-based Services) is increasing. IndoorGML (Indoor Geographic Markup Language) has been established as the data standard for spatial data in providing indoor navigation, but its definitions and relationships must be expanded to increase its applications and to successfully delivering information to users. In this study, we propose an approach to integrate IndoorGML with Indoor POI (Points of Interest) data by extending the IndoorGML notion of space and topological relationships. We consider two cases of representing Indoor POI, by 3D geometry and by point primitive representation. Using the concepts of the NRS (node-relation structure) and multi-layered space representation of IndoorGML, we define layers to separate features that represent the spaces and the Indoor POI into separate, but related layers. The proposed methodology was implemented with real datasets to evaluate its effectiveness for performing indoor spatial analysis.

• 대한공간정보학회지
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• 제18권2호
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• pp.55-61
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• 2010

본 연구는 지상라이다로부터 획득한 3차원 점 데이터를 이용하여 구축된 공간자료를 격자(gridded) 및 비격자(un-gridded)로 구분하여 모델링을 실시하였고, 이러한 모델링 결과를 이용하여 가시선 분석 실험을 실시하였다. 두 모델의 형태에 따른 가시선 분석 결과를 비교하기 위하여 본 연구에서는 실험지역의 가시선 최대 도달거리를 A지역 30m, B지역 40m, C지역 50m로 구분하였고, 가시선 분석 소요 시간과 가시되는 점의 개수를 측정하였다. 실험 결과를 살펴보면, 비격자모델의 경우, 격자모델에 비해 지역별로 A지역은 약 3.9배, B지역은 약 5.4배, C지역은 약 6.5배 정도 많은 시간이 가시선 분석에 소요되었으며, A지역은 약 0.97배, B지역은 약 0.93배, C지역은 약 0.94배 정도 적은 가시점 개수가 측정되었다. 가시선 분석 소요시간은 가시선의 최대도달거리가 증가함에 따라 격자모델과 비격자 모델의 차이가 증가함을 알 수 있고, 반면에 가시되는 점의 개수는 가시반경의 크기에 크게 영향을 받지 않았다.

• Journal of Construction Engineering and Project Management
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• 제2권3호
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• pp.1-7
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• 2012

The reconstruction of surfaces from unorganized point clouds can provide very useful information for construction managers. Although point clouds are generally created using 3D scanners, they can also be generated via the structure-from-motion technique using a sequence of images. Here we report a novel surface reconstruction technique for modeling and quantifying earthworks that can be used for preliminary planning, project updates and estimating of earthwork quantities, as well as embedded planning systems in construction equipment. The application of structure-from-motion techniques in earth works is examined and its advantages and limitations identified. Data from 23 earthwork excavation construction sites were collected and analyzed. 3D surface reconstructions during the construction phase were compared to the original land form. Similar experiments were conducted with piles of earth and the results analyzed to determine appropriate ranges of use for structure-from-motion surface reconstructions in earthwork applications. The technique was found to be most suited to pile of materials with volumes less than 2000 m3. Piles up to 10 m in height and with base areas up to $300m^2$ were also successfully reconstructed. These results should be of interest to contractors seeking to utilize new technology to optimize operational efficiency.

• 한국CDE학회논문집
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• 제14권2호
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• pp.96-104
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• 2009

It gradually becomes important to study on how to efficiently integrate and manage plant lifecycle data such as 2D schematic and 3D solid data, logical configuration data, and equipment specifications data. From this point of view, converting plant design data from various systems into neutral data independent from any commercial systems is one of important technologies for the operation and management of plants which usually have a very long period of life. In order to achieve this goal, a neutral model for efficient integration and management of plant data was defined. After schema mapping between one of specification-driven plant design systems and the neutral model was performed, a plant data translator is also implemented according to the mapping result. Finally, by experiments with nuclear power plant design, the feasibility of the translator was demonstrated.

• 한국정보통신학회논문지
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• 제25권5호
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• pp.652-658
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• 2021

3D 스캐너를 이용하여 점군을 획득 시 각각의 고유한 좌표를 기준으로 취득한 데이터를 통일된 좌표체계를 가진 하나의 데이터로 만드는 과정이 필요하고 이 과정을 정합이라고 한다. 정합 과정은 한 번의 수행으로 만족할만한 결과를 얻기 힘들며 여러 차례 반복하여 정합 정밀도를 높인다. 정합의 정밀도를 판단하는 기준은 중요한 요소이다. 기존에 정합의 정밀도를 파악하는 방법은 경우에 따라 판단 기준이 모호할 수 있으며, 점군 데이터의 특성에 따라 매번 다른 결과가 나올 수 있는 한계점을 가지고 있다. 이에 본 연구에서는 정합의 정밀도는 좀 더 정확하게 계산하기 위하여 정합에서 사용하는 대응점이 아닌 전체 점군에 대해서 점군의 평균 거리 값을 이용한 방법을 제안한다. 이 방법을 사용할 경우 기존의 방법에 비하여 좀 더 확실하게 정합의 정밀도를 파악할 수 있다.