• Title, Summary, Keyword: 지상 LiDAR

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Comparative Accuracy of Terrestrial LiDAR and Unmanned Aerial Vehicles for 3D Modeling of Cultural Properties (문화재 3차원 모델링을 위한 지상 LiDAR와 UAV 정확도 비교 연구)

  • Lee, Ho-Jin;Cho, Gi-Sung
    • Journal of Cadastre & Land InformatiX
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    • v.47 no.1
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    • pp.179-190
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    • 2017
  • A terrestrial LiDAR survey was conducted and unmanned aerial vehicle(UAV) images were taken for target cultural properties to present the utilization measures of terrestrial LiDAR and UAV in three-dimensional modeling of cultural properties for the identification of the status and restoration of cultural properties. Then the accuracy of the point clouds generated through this process was compared, an overlap analysis of the 3D model was conducted, and a convergence model was created. According to the results, the modeling with terrestrial LiDAR is more appropriate for precise survey because 3D modeling for the detection of displacement and deformation of cultural properties requires an accuracy of mm units. And UAV model has limitation as the impossibility of detailed expression of parts with sharp unevenness such as cracks of bricks. However, it is found that the UAV model has a wide range of modeling and has the advantage of modeling of real cultural properties. Finally, the convergence model created in this study using the advantages of the terrestrial LiDAR model and the UAV model could be efficiently utilized for the basic data development of cultural properties.

Comparison of Drone and Terrestrial LiDAR DEM generation data for Analyzing Estuary Topographic Changes (하구부 지형변화 분석을 위한 드론과 지상LiDAR DEM 생성자료의 비교)

  • Lee, Jeong Hoon;Jun, Kye Won
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.140-140
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    • 2017
  • 최근 기후변화에 따른 태풍과 국지성 집중호우의 증가로 국토의 64%가 산지인 우리나라에서는 재해의 위험성을 증가시키고 있다. 재해 분석에 있어 기초자료로 사용되는 지형자료의 정확도는 재해분석결과에 있어 중요하며, 지형촬영방법에 따라 정확도의 차이가 매우 크다. 지형자료 중 하나인 DEM(Digital Elevation Model) 활용분야 또한 확대되고 있고 지도제작에 있어 DEM을 사용하면 지형도를 신속히 제작할 수 있고, 편집 용이, 수작업 인원 감축, 정확도 향상 및 데이터베이스의 구축이 이루어져 체계적으로 종합적인 지형정보를 관리할 수 있는 장점이 있다. 지상 LiDAR를 이용하여 생성한 DEM은 매우 정확한 방법이며, 접촉식 측량장비에 비하여 누락되는 데이터가 적으며 정밀하게 자료를 수집가능 한 것이 장점이다. 지상LiDAR를 이용한 자료 취득 시식생과 구조물에 의해 촬영 각도가 제한되는 경우 충분한 자료를 얻기 위해 여러 위치에서 스캔이 필요하다. 한편 전 세계적으로 드론의 도입으로 인해 다양한 분야에서 높은 가능성을 가지고 활용되고 있는 실정이며, 드론을 이용한 연구들도 활발히 진행 중이다. 소규모 및 중간 규모의 하천, 산지 등의 현장 조사의 경우 LiDAR장비의 진입이 어려운 구간의 촬영 시 드론을 활용하면 보다 효율적일 것으로 예상된다. 이에 따라 본 연구는 지상LiDAR와 드론을 이용하여 얻은 DEM 자료를 비교 분석하여 드론으로 생성된 DEM 자료 활용 가능성 여부를 검토하였다. 본 연구에서는 동일한 지역에 지상LiDAR와 드론 촬영을 실시하여 지형자료를 각각 획득한 후 후처리 프로그램을 이용하여 영상분석을 실시하였다. 또한 측점을 선정한 후 지형 좌표의 편차, 표고의 편차 등을 비교분석하였다.

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A Studies on the Bed Elevation Variation for an estuary using LiDAR (하구지역 하상변화 분석을 위한 지상 LiDAR의 활용)

  • Jun, Kye-Won;Ahn, Myung-Gil;Jun, Byong-Hee;Jang, Chang-Deok;Park, Hwan-Seul
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.466-466
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    • 2012
  • 하천의 하구에서는 해수의 흐름에 따른 연안토사의 이동과 하천유황에 따른 상류에서의 토사량에 따라 하상이 변화한다. 특히 하구부에서의 퇴적토사 증가는 하천의 수질변화와 어도단절 등으로 인해 하천환경에 악영향을 끼칠 수 있는 하구폐쇄를 발생시킬 수 있어 이에 따른 모니터링이 필요하다. 본 연구에서는 동해안으로 유출되는 지방 1급 하천인 가곡천과 호산천을 대상으로 하구부 퇴적토사의 변화를 모니터링 하였다. 하상변화의 모니터링은 최신장비인 지상 LiDAR를 이용하여 다시기로 스캔한 지상 LiDAR 측정자료를 활용하여 퇴적량을 산출하고 퇴적과 침식의 변화양상을 분석하였다. 분석결과 퇴적지점과 침식지점 및 이에 대한 체적량 변화를 정밀하게 확인할 수 있었다. 지상 LiDAR를 활용한 하상변화 분석기법은 정밀한 퇴적량 추이를 빠르게 관찰할 수 있어 하구지역 뿐만 아니라 하천 전반에서의 하상변화를 조사하는 데에 있어 활용도가 높을 것으로 판단된다.

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Tunnel Reverse Engineering Using Terrestrial LiDAR (지상LiDAR를 이용한 터널의 Reverse Engineering)

  • Cho, Hyung Sig;Sohn, Hong Gyoo;Kim, Jong Suk;Lee, Suk Kun
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.6D
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    • pp.931-936
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    • 2008
  • Surveying by using terrestrial LiDAR(Light Detection And Ranging) is more rapid than by using total station which enables tunnel section profile surveying to be done in suitable time and minimize centerline error, occurrence of overcut and undercut. Therefore, utilization of terrestrial LiDAR has increased more and more in section profile survey and measurement field Moreover, studies of terrestrial LiDAR for accurate and efficient utilization is now ongoing vigorously. Average end area formula, which was generally used to calculate overcut and undercut, was compared with existing methods such as total station survey and photogrammetry. However, there are no criteria of spacing distance for calculating overcut and undercut through terrestrial LiDAR surveying which can acquire 3D information of whole tunnel. This research performed reverse engineering to decide optimal spacing distance when surveying tunnel section profile by comparing whole tunnel volume and tunnel volume in difference spacing distance. This result was utilized to produce CAD drawing for the test tunnel site where there is no design drawings. In addition to this, efficiency of LiDAR and accuracy of CAD drawing was compared with targetless total station surveying of tunnel section profile. Finally, error analysis of target coordinate's accuracy and incidence angle was done in order to verify the accuracy of terrestrial LiDAR technology.

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Application of Terrestrial LiDAR to Monitor Unstable Blocks in Rock Slope (암반사면 위험블록 모니터링을 위한 지상 LiDAR의 활용)

  • Song, Young-Suk;Lee, Choon-Oh;Oh, Hyun-Joo;Pak, Jun-Hou
    • The Journal of Engineering Geology
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    • v.29 no.3
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    • pp.251-264
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    • 2019
  • The displacement monitoring of unstable block at the rock slope located in the Cheonbuldong valley of Seoraksan National Park was carried out using Terrestrial LiDAR. The rock slopes around Guimyeonam and Oryeon waterfall where rockfall has occurred or is expected to occur are selected as the monitoring section. The displacement monitoring of unstable block at the rock slope in the selected area was performed 5 times for about 7 months using Terrestrial LiDAR. As a result of analyzing the displacement based on the Terrestrial LiDAR scanning, the error of displacement was highly influenced by the interpolation of the obstruction section and the difference of plants growth. To minimize the external influences causing the error, the displacement of unstable block should be detected at the real scanning point. As the result of analyzing the displacement of unstable rock at the rock slope using the Terrestrial LiDAR data, the amount of displacement was very small. Because the amount of displacement was less than the range of error, it was difficult to judge the actual displacement occurred. Meanwhile, it is important to select a section without vegetation to monitor the precise displacement of unstable rock at the rock slope using Terrestrial LiDAR. Also, the PointCloud removal and the mesh model analysis in a vegetation section were the most important work to secure reliability of data.

Experiment of Computation of Ground Cutting Volume Using Terrestrial LiDAR Data (지상 LiDAR 자료의 절토량 산정 실험)

  • Kim, Jong-Hwa;Pyeon, Mu-Wook;Kim, Sang-Kuk;Hwang, Yeon-Soo;Kang, Nam-Gi
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.2
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    • pp.11-17
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    • 2009
  • Terrestrial LiDAR can measure high capacity 3D-topography coordinates and try to apply to various public works such as tunnel surveying, facility deformation surveying. This experiment is about how to calculate ground cutting volume because the stage of the earth work spend lots of money and time among civil engineering works. Surveying cutting area using Terrestrial LiDAR and then calculating cutting area in planned area comparing sectional plan before construction and planned section and LiDAR data. Also, the values of the calculating ground cutting volume by three different resolution LiDAR has are compared and analyzed.

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Construction of 3D Spatial Information of Vertical Structure by Combining UAS and Terrestrial LiDAR (UAS와 지상 LiDAR 조합에 의한 수직 구조물의 3차원 공간정보 구축)

  • Kang, Joon-Oh;Lee, Yong-Chang
    • Journal of Cadastre & Land InformatiX
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    • v.49 no.2
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    • pp.57-66
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    • 2019
  • Recently, as a part of the production of spatial information by smart cities, three-dimensional reproduction of structures for reverse engineering has been attracting attention. In particular, terrestrial LiDAR is mainly used for 3D reproduction of structures, and 3D reproduction research by UAS has been actively conducted. However, both technologies produce blind spots due to the shooting angle. This study deals with vertical structures. 3D model implemented through SfM-based image analysis technology using UAS and reproducibility and effectiveness of 3D models by terrestrial LiDAR-based laser scanning are examined. In addition, two 3D models are merged and reviewed to complement the blind spot. For this purpose, UAS based image is acquired for artificial rock wall, VCP and check point are set through GNSS equipment and total station, and 3D model of structure is reproduced by using SfM based image analysis technology. In addition, Through 3D LiDAR scanning, the 3D point cloud of the structure was acquired, and the accuracy of reproduction and completeness of the 3D model based on the checkpoint were compared and reviewed with the UAS-based image analysis results. In particular, accuracy and realistic reproducibility were verified through a combination of point cloud constructed from UAS and terrestrial LiDAR. The results show that UAS - based image analysis is superior in accuracy and 3D model completeness and It is confirmed that accuracy improves with the combination of two methods. As a result of this study, it is expected that UAS and terrestrial LiDAR laser scanning combination can complement and reproduce precise three-dimensional model of vertical structure, so it can be effectively used for spatial information construction, safety diagnosis and maintenance management.

Slope transformation detection by using Terrestrial LiDAR data (지상 LiDAR자료를 이용한 사면변화 탐지)

  • Park, Keon;Yang, In-Tae;Choi, Seung-Pil;Kim, Sung-Hak
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • pp.318-323
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    • 2008
  • 국부적이지만 수 mm단위까지 스캔이 가능한 지상LiDAR 장비를 이용하여 사면을 스캐닝한 후에 사면의 6개 지점에 대하여 강제로 변화를 준 후 다시 스캐닝하여 분석한 결과 0.008m의 평균편차를 나타내었다. 이것을 볼 때 미세변화 탐지를 위한 기법으로 지상 LiDAR자료의 적용이 유효할 것으로 판단된다.

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Evaluation for Earthwork Slope Safety Using Terrestrial LiDAR (지상 LiDAR를 이용한 토공 사면의 안정성 평가)

  • Kim, Hee-Gyoo;Roh, Tae-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.17 no.3
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    • pp.82-92
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    • 2014
  • The ratio of using soil as the main material in construction is quite numerous, and it covers many parts in forms and bases of the structure. Thus, the earthwork forms many structures for social infrastructure, and the stability of these structures is most crucial when completed than under construction. This study executed a field experiment to evaluate the accuracy and utility of the slope, which is an important part in earthwork, when terrestrial LiDAR is obtained, and the results are as follow. First, as the result of the observation using Total Station and terrestrial LiDAR, the horizontal error RMSE was ${\pm}2.2cm$, and the vertical error RMSE was ${\pm}3.0cm$. As the result of the comparison between the errors and permissible range of public surveying regulation, it sufficiently secure the accuracy. Also, the extraction of the check section, which covers the most important part among the stability checks could be scientifically and rationally processed, and these extraction results are expected to be provided as important basic materials for the earthwork slop stability evaluation.

A Study of Monitoring in Slopes of High Collapse Risk Using Terrestrial LiDAR (지상 LiDAR를 이용한 위험관리사면의 변위 모니터링)

  • Park, Jae-Kook
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.45-52
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    • 2010
  • One of the ways to minimize damage by a slope collapse is to set up preventive measures in advance by measuring displacements in a slope and predicting a collapse. There have been many different technologies developed to predict a collapse with diverse measuring equipment. Especially recently, attempts have been made to utilize terrestrial LiDAR, a high-tech imaging equipment to measure displacements on a scope. Terrestrial LiDAR generates three-dimensional information about an object with millimeter-level accuracy from hundreds of meters away and has been used in an array of fields including restoration of cultural assets, three-dimensional modeling, and making of topographic maps. In recent years, it has been used to measure displacements in structure as well. This study monitored displacements in slopes of high collapse risk with terrestrial LiDAR. As a result, it was able to confirm the applicability of terrestrial LiDAR to the field, and proposed monitoring methods.