• Title, Summary, Keyword: 지상기준점

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Automatic Measuring of GCP's Image Coordinates from SPOT Satellite Imagery (SPOT 위성영상에서의 지상기준점의 영상좌표 자동관측)

  • 강명호;방수남;이용웅
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • pp.354-362
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    • 2003
  • 위성영상으로부터 위치자료가 포함된 지리 및 지형정보를 얻기 위해서는 영상획득순간의 센서 위치 및 자세와 지상좌표간의 관계를 해석하여야 한다. 위성영상에 대한 수학적 모형화를 위해서 먼저 입체영상에서 지상기준점(Ground Control Point: GCP)을 선정하고, 선정된 지상기준점에 대한 지상좌표 및 대상영상에 대한 영상좌표 관측작업을 수행한다. 본 연구에서는 지상기준점 데이터베이스에 포함된 정보들을 이용하여 관측대상 입체영상 3차원 모형화에 필요한 지상기준점의 영상좌표를 자동으로 추출할 수 있는 기법을 개발하였다. 관측정밀도는 수작업으로 관측한 값과 자동계산된 영상좌표의 결과를 비교 분석하여 평가하였으며, SPOT위성영상의 3차원 모형화에 적용하여 정확도를 평가하므로써 유사한 해상도의영상을 활용하는 3차원 모형화 과정에서 지상기준점의 영상좌표 관측을 자동화 할 수 있음을 입증하였다.

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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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Generation of GCP from SAR data (영상 레이더를 이용한 지상 기준점 추출)

  • 홍상훈;정형섭;이호남;원중선
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • pp.115-120
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    • 2003
  • 일반적으로 광학위성은 궤도가 부정확하여 지상기준점(GCP)을 이용하여 궤도를 보정하는 작업을 수행한 후 수치 표고모형 자료(DEM)를 추출한다. 지상기준점은 실제 측량이나 지형도로부터 얻게 되지만, 이러한 작업이 불가능한 경우에는 광학영상으로부터 수치 표고 모형 자료를 추출할 수 없다. 본 연구에서는 수-수십 cm의 위성 궤도 정확도를 지니는 ESA ERS영상과 약 1Km의 해상도를 지니는 GTOPO-30 DEM을 이용하여 지상기준점을 추출 방법에 대해 연구하였다. 연구지역인 대전 주변에 대하여 지상기준점을 추출한 결과 경도 -0.348초, 위도 0.293초의 오차를 나타내었다. 또한 추출된 지상기준점을 이용하여 한 쌍의 SPOT 위성영상으로부터 DEM을 추출이 가능하였으며, 레이더 interferometry 기술을 이용한 지형고도 추출 및 변화 탐지에도 활용될 수 있음을 확인하였다.

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SPOT Camera Modeling Using Ephemeris Data (궤도자료를 이용한 SPOT 카메라 모델링)

  • 김만조;차승훈;고보연
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • pp.531-536
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    • 2003
  • In this paper, a camera modeling method that utilizes ephemeris data and imaging geometry is presented. The proposed method constructs a mathematical model only with parameters that are contained in the leader file and does not require any ground control points for model construction. Control points are only needed to eliminate geolocation error of the model that is originated from errors in the parameters that are used in model construction. With few (one or two) of control points, RMS error of less than pixel size can be obtained and control points are not necessarily uniformly distributed over the entire scene. This advantage is crucial in large project and will enable to reduce project cost dramatically.

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Automatic Measuring of GCP's Image Coordinates using Control Point Patch and Auxiliary Points Matching (기준점 패치 및 보조점 정합에 의한 지상기준점의 영상좌표 자동관측)

  • Kang, Myung-Ho;Bang, Soo-Nam;Lee, Yong-Woong
    • Journal of Korean Society for Geospatial Information Science
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    • v.11 no.2
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    • pp.29-37
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    • 2003
  • An approach is described for automatic measuring of GCP's image coordinates from SPOT imagery and focused on the fulfillment an automatic orientation of satellite images. For the orientation of a stereopair of digital images, firstly, GCP(Ground Control Point) should be selected and then the work for measuring of image coordinates correspond to GCPs is required. In this study, we propose the method for extracting the GCP's image coordinates automatically using an image patch for control points and auxiliary points matching. For the evaluation of measurement accuracy, a comparison between points those are extracted manually and automatically by a proposed method have made. Finally, we shows the feasibility of automatic image coordinates measurment by applying in stereo modeling for SPOT images.

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Estimating Accuracy of 3-D Models of SPOT Imagery Based on Changes of Number of GCPs (SPOT영상을 사용한 3차원 모델링시 지상기준점수에 따른 정확도 평가)

  • 김감래;안병구;김명배
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.1
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    • pp.61-69
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    • 2003
  • There is various kinds cause that influence to created DEM and orthoimage using stereo satellite images. Specialty, research about effect that GCP number gives to accuracy of DEM, orthoimage and modeling may have to be gone ahead. Therefore, this research increases GCP number by 5 to 30 and created each modeling, DEM and orthoimage using SPOT panchromatic images that resolution is 10m by digital image processing method. Accuracy assessment did by orthoimage using 20 check point. As a result, GCP number between 10∼30 modeling RMSE is 1 pixel low appear. Horizontal·vertical error that use orthoimage looked tendency that decrease GCP number increases, and confirmed by the most economical in GCP number 10∼15. Also, analyze correlation of GCP number and orthoimage position accuracy and presented improvement plan and research task hereafter.

Extraction of Ground Control Points from TerraSAR-X Data (TerraSAR-X를 이용한 지상기준점 추출)

  • Park, Jeong-Won;Hong, Sang-Hoon;Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.24 no.4
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    • pp.299-307
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    • 2008
  • It is possible to extract qualified ground control points (GCPs) from SAR data itself without published maps. TerraSAR-X data that are one of highest spatial resolution among civilian SAR systems is now available. In this study, a sophisticated method for GCP extraction from TerraSAR-X data was tested and the quality of the extracted GCPs was evaluated. Mean values of the distance errors were 0.11m and -3.96 m with standard deviations of 6.52 m and 5.11 m in easting and northing, respectively. The result is one of the best among GCPs possibly extracted from any civilian remote sensing systems. The extracted GCPs were used for geo-rectification of IKONOS image. The method used in this study can be applied to KOMPSAT-5 for geo-rectification of high-resolution optic images acquired by KOMPSAT-2 or follow-up missions.

Improving the Accuracy of 3D Object-space Data Extracted from IKONOS Satellite Images - By Improving the Accuracy of the RPC Model (IKONOS 영상으로부터 추출되는 3차원 지형자료의 정확도 향상에 관한 연구 - RPC 모델의 위치정확도 보정을 통하여)

  • 이재빈;곽태석;김용일
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.4
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    • pp.301-308
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    • 2003
  • This study describes the methodology that improves the accuracy of the 3D object-space data extracted from IKONOS satellite images by improving the accuracy of a RPC(Rational Polynomial Coefficient) model. For this purpose, we developed the algorithm to adjust a RPC model, and could improve the accuracy of a RPC model with this algorithm and geographically well-distributed GCPs(Ground Control Points). Furthermore, when a RPC model was adjusted with this algorithm, the effects of geographic distribution and the number of GCPs on the accuracy of the adjusted RPC model was tested. The results showed that the accuracy of the adjusted RPC model is affected more by the distribution of GCPs than by the number of GCPs. On the basis of this result, the algorithm using pseudo_GCPs was developed to improve the accuracy of a RPC model in case the distribution of GCPs was poor and the number of GCPs was not enough to adjust the RPC model. So, even if poorly distributed GCPs were used, the geographically adjusted RPC model could be obtained by using pseudo_GCPs. The less the pseudo_GCPs were used -that is, GCPs were more weighted than pseudo_GCPs in the observation matrix-, the more accurate the adjusted RPC model could be obtained, Finally, to test the validity of these algorithms developed in this study, we extracted 3D object-space coordinates using RPC models adjusted with these algorithms and a stereo pair of IKONOS satellite images, and tested the accuracy of these. The results showed that 3D object-space coordinates extracted from the adjusted RPC models was more accurate than those extracted from original RPC models. This result proves the effectiveness of the algorithms developed in this study.

Utilization of Ground Control Points using LiDAR Intensity and DSM (LiDAR 반사강도와 DSM을 이용한 지상기준점 활용방안)

  • Lim, Sae-Bom;Kim, Jong-Mun;Shin, Sang-Cheol;Kwon, Chan-O
    • Spatial Information Research
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    • v.18 no.5
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    • pp.37-45
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    • 2010
  • AT(Aerial Triangulation) is the essential procedure for creating orthophoto and transforming coordinates on the photographs into the real world coordinates utilizing GCPs (Ground Control Point) which is obtained by field survey and the external orientation factors from GPS/INS as a reference coordinates. In this procedure, all of the GCPs can be collected from field survey using GPS and Total Station, or obtained from digital maps. Collecting GCPs by field survey is accurate than GCPs from digital maps; however, lots of manpower should be put into the collecting procedure, and time and cost as well. On the other hand, in the case of obtaining GCPs from digital maps, it is very difficult to secure the required accuracy because almost things at each stage in the collecting procedure should rely on the subjective judgement of the performer. In this study, the results from three methods have been compared for the accuracy assessment in order to know if the results of each case is within the allowance error: for the perceivable objects such as road boarder, speed bumps, constructions etc., 1) GCPs selection utilizing the unique LiDAR intensity value reflected from such objects, 2) using LiDAR DSM and 3) GCPs from field survey. And also, AT and error analysis have been carried out w ith GCPs obtained by each case.

SPOT Camera Modeling Using Auxiliary Data (영상보조자료를 이용한 SPOT 카메라 모델링)

  • 김만조;차승훈;고보연
    • Korean Journal of Remote Sensing
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    • v.19 no.4
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    • pp.285-290
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    • 2003
  • In this paper, a camera modeling method that utilizes ephemeris data and imaging geometry is presented. The proposed method constructs a mathematical model only with parameters that are contained in auxiliary files and does not require any ground control points for model construction. Control points are only needed to eliminate geolocation error of the model that is originated from errors embedded in the parameters that are used in model construction. By using a few (one or two) control points, RMS error of around pixel size can be obtained and control points are not necessarily uniformly distributed in line direction of the scene. This advantage is crucial in large-scale projects and will enable to reduce project cost dramatically.