• Title/Summary/Keyword: 검사점측량

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Evaluation of Airborne LiDAR Data using Field Surveyed Ground Control Points (현지 측량기준점을 이용한 LiDAR 데이터의 정확도 검증)

  • Wie, Gwang-Jae;Yang, In-Tae;Suh, Young-Woon;Sim, Jung-Min
    • Journal of Korean Society for Geospatial Information Science
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    • v.14 no.4 s.38
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    • pp.11-18
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    • 2006
  • In this paper, airborne LiDAR data were evaluated in horizontal and vertical accuracy. By using zigzag scanning type of LiDAR, GCPs are not tested directly. So points around GCPs were used in this evaluation. Building corner points were made from LiDAR's building planar and compared with ground surveyed GCPs, in horizontal accuracy test. Its accuracy shows 19cm average and 21cm RMSE and 15 points were within 20cm among 16 points. In vertical accuracy test, 41 GCPs were used and it shows 11cm average and 14cm RMSE and 75% of GCPs were within 15cm. This could be a criterion in topographic map modification and basic geographic DB and 3D data construction using airborne LiDAR data.

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Accuracy Evaluation of LiDAR Measurement in Forest Area (산림지역에서 LiDAR 측량의 정확도 평가)

  • Lee, Sang-Hoon;Lee, Byoung-Kil;Kim, Jin-Kwang;Kim, Chang-Jae
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.5
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    • pp.545-553
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    • 2009
  • Digital Elevation Models (DEM) is widely used in establishing the topographic profile in nation spatial information. Aerial Light Detection And Ranging (LiDAR) system is one of the well-known means to produce DEM. The system has fast data acquisition procedures and less weather-dependent restrictions compared to photogrammetric approaches. In this regards, LiDAR has been widely utilized and accepted in the process of nation spatial information generation due to its sufficient positional accuracy. However, the investigation of the accuracy of aerial LiDAR data over the area of forestation with various kinds of vegetations has been barely implemented in Korea. Hence, this research focuses on the investigation of the accuracy of aerial LiDAR data over the area of forestation and the evaluation of the acquired accuracy according to the characteristics of the vegetations. The study areas include land with shrubs and its adjacent forest area with mixed tree species. The spots for the investigation have been selected to be well-distributed over the whole study areas and their coordinates are surveyed by Global Positioning Systems (GPS). Then, the surveyed information and aerial LiDAR data have been compared with each other and the result accuracy has been evaluated. Conclusively, it is recommended that LiDAR data collection to be conducted after defoliation period, especially over the areas with broadleaf trees due to the possibility of significant outliers.

Accuracy Analysis of Medium Format CCD Camera RCD105 (중형카메라 RCD105 정확도 분석)

  • Kim, Tae-Hoon;Won, Jae-Ho;Kim, Chung-Pyeong;So, Jae-Kyeong;Yun, Hee-Cheon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.4
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    • pp.449-454
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    • 2010
  • Lately, airborne digital camera and airborne laser scanner in field of airborne surveying are used to build geography information such as digital ortho photo map and DEM(Digital Elevation Model). In this study, 3D position accuracy is compared medium format CCD camera RCD105 with airborne digital camera DMC. For this, test area was decided for aerial photograph. And using 1/1,000 scale digital map, ground control points were selected for aerial triangulation and check points were selected for horizontal/vertical accuracy analysis using softcopy stereoplotter. Accuracy of RCD105 and DMC was estimated by result of aerial triangulation and result of check points measurement of using softcopy stereoplotter. In result of aerial triangulation, RMSE(Root Mean Square Error) X, Y, Z of RCD105 is 2.1, 2.2, 1.3 times larger than DMC. In result of check point measurement using softcopy stereoplotter, horizontal/ vertical RMSE of RCD105 is 2.5, 4.3 times larger than DMC. Even though accuracy of RCD105 is lower than DMC, it is maybe possible to make digital map and ortho photo using RCD105.

Aircraft Deformation Measurement using Industrial Photogrammetry (산업사진측량기법을 이용한 항공기 변형 측정)

  • Lee Jae-Kee;Jung Sung-Heuk;Yu Jung-Hum
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.23 no.2
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    • pp.205-210
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    • 2005
  • As industries developed, industrial goods have got more precise. It led producers to feel like having a way to confirm whether the goods are good enough for the needs of consumers or not. Because of that, producers got interested in industrial photogrammetry that can get accurate data quickly with non-confect method. therefore, this study was examined by photographing an O-2A aircraft which was a large and precise one to check the application of Industrial photogrammetry. To measure the aircraft, the check points, that was attached to it was used as it was not possible to measure the aircraft by its design. The experiment was carried out in three parts considering arrangement of the check points and measured with Pro-spot to check any deformation of its external form. As a result, this study enables us to conferm a state of the aircraft alignment promptly and to provide accurate data for producers, which helps them to make a decision.

Underground Facility Survey and 3D Visualization Using Drones (드론을 활용한 지하시설물측량 및 3D 시각화)

  • Kim, Min Su;An, Hyo Won;Choi, Jae Hoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.1
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    • pp.1-14
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    • 2022
  • In order to conduct rapid, accurate and safe surveying at the excavation site, In this study, the possibility of underground facility survey using drones and the expected effect of 3D visualization were obtained as follows. Phantom4Pro 20MP drones have a 30m flight altitude and a redundant 85% flight plan, securing a GSD (Ground Sampling Distance) value of 0.85mm and 4points of GCP (Groud Control Point)and 2points of check point were calculated, and 7.3mm of ground control point and 11mm of check point were obtained. The importance of GCP was confirmed when measured with low-cost drones. If there is no ground reference point, the error range of X value is derived from -81.2 cm to +90.0 cm, and the error range of Y value is +6.8 cm to 155.9 cm. This study classifies point cloud data using the Pix4D program. I'm sorting underground facility data and road pavement data, and visualized 3D data of road and underground facilities of actual model through overlapping process. Overlaid point cloud data can be used to check the location and depth of the place you want through the Open Source program CloudCompare. This study will become a new paradigm of underground facility surveying.

Application of CCD Image by Direct Georeferencing (Direct Georeferencing에 의한 CCD 영상의 적용기법)

  • Song Youn Kyung;Park Woon Yong;Park Hong Gi
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.23 no.1
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    • pp.77-88
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    • 2005
  • Direct Georeferencing (DG) is based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The methods can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. In this study, a CCD camera is simultaneously used in GPS/INS, and acquired CCD image through Direct Georeferencing produce digital orthoimage. In this process, methods of combining sensor and digital orthoimage are examined and estimated. For the comparison of the positioning accuracy digital orthoimage through Direct Georeferencing, GCPs determined by GPS surveying are used. Two digital orthoimage are produced; one with a few GCP and the other without them. The produced maps can be used to correct or revised 1:1,000 or 1:5,000 scale maps accordingly.

Process of Digital Elevation Model Using RC Helicopter Surveying System (무선조정 헬리콥터 사진측량시스템을 이용한 수치표고모형 작성)

  • Jang, Ho-Sik
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.2
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    • pp.111-116
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    • 2008
  • The study installed non metric camera which was a 10 Mega Pixel camera in RC Helicopter. And the study controlled images hotographed in air on land, considering their overlap. The study could express DEM by abstracting TIN from the acquired images through image registration. Also, the study compared and examined accuracy between reference point and check point observed by Total Station which was a conventional type of survey. As the results, the study could get errors of $-0.194{\sim}0.224\;m$ on X axis, $-0.088{\sim}0.180\;m$ on Y axis and $-0.286{\sim}0.285\;m$ on Z axis. Expressing an error's RMSE in the checkpoint, the study could get of 0.021388 m on X axis, 0.015285 m on Y axis and 0.041872 m on Z axis. It is judged that the above photographing and analyzing technique are better than the existing Total Station to acquire more terrain elevation data.

Updating of Digital Map using Digital Image and LIDAR (디지털 영상과 LIDAR 자료를 이용한 수치지도 갱신)

  • Yun, Bu-Yeol;Hong, Jung-Soo
    • Journal of the Korean Geophysical Society
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    • v.9 no.2
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    • pp.87-97
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    • 2006
  • LIDAR(Light Detection and Ranging) is a new technology for obtaining DEM(Digital Elevation Model)ewith high density and high point acuracy. As LIDAR emerged, DEM could be developed in the earthsurface more efficiently and more economically, compared to the conventional aerial photogrametry.In this study, a digital camera is simultaneously used in combined LIDAR surveying, and acquired digitial image and DEM produce digital orthoimage. In this process, methods of combining sensor andorthoimage, GCPs determined by GPS surveying are used. Two digital orthoimage are produced; onewith a few GCP and the other without them. The produced maps can be used to corect or revised1:1,000 or 1:5,000 scale maps acordingly.

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Accuracy Comparison Of Ground Control Points extracting from LIDAR Intensity (라이다의 반사강도에서 추출한 지상기준점의 정확도 비교)

  • Wie, Gwang-Jae;Choi, Yun-Soo;Oh, Jong-Min;Lee, Im-Pyung;Suh, Young-Woon
    • Journal of Korean Society for Geospatial Information Science
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    • v.16 no.4
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    • pp.25-31
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    • 2008
  • As we choose ground control points for aerial triangulation, we have a lot of problems in a mountain, a costal area, a desert, the foreshore etc because they don't have clear topography for control points and it spends a lot of cost and occurs problems of accuracy. In this study, we compare and analyze between ground control points from LiDAR intensity, digital map with ground control points from the field survey as doing AT each. As the result, the average error was ${\pm}1.02m$ from using LiDAR intensity, ${\pm}1.13m$ from using digital map. this result can present the control points from LiDAR intensity is 0.11m better than from digital map.

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A Study on 3D Model Building of Drones-Based Urban Digital Twin (드론기반 도심지 디지털트윈 3차원 모형 구축에 관한 연구)

  • Lim, Seong-Ha;Choi, Kyu-Myeong;Cho, Gi-Sung
    • Journal of Cadastre & Land InformatiX
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    • v.50 no.1
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    • pp.163-180
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    • 2020
  • In this study, to build a spatial information infrastructure, which is a component of a smart city, a 3D digital twin model in the downtown area was built based on the latest spatial information acquisition technology, the drone. Several analysis models were implemented by utilizing. While the data processing time and quality of the three types of drone photogrammetry software are different, the accuracy of the construction model is ± 0.04 in the N direction and ± 0.03m in the E direction. In the m and Z directions, ± 0.02m was found to be less than 0.1m, which is defined as the allowable range of surveying performance and inspection performance for the boundary point in the area where the registration of the boundary point registration is executed. 1: 500 to 1 of the aerial survey work regulation: The standard deviation, which is the error limit of the photographic reference point of the 600 scale, appeared within 0.14 cm, and it was found that the error limit of the large scale specified in the cadastral and aerial survey was satisfied. In addition, in order to increase the usability of smart city realization using a drone-based 3D urban digital twin model, the model built in this study was used to implement Prospect right analysis, landscape analysis, Right of light analysis, patrol route analysis, and fire suppression simulation training. Compared to the existing aerial photographic survey method, it was judged that the accuracy of the naked eye reading point is more accurate (about 10cm) than the existing aerial photographic survey, and it is possible to reduce the construction cost compared to the existing aerial photographic survey at a construction area of about 30㎢ or less.