• Title/Summary/Keyword: Indirect georeferencing

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Accuracy Comparison of Direct Georeferencing and Indirect Georeferencing in the Mobile Mapping System

  • Bae Sang-Keun;Kim Byung-Guk;Sung Jung-Gon
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.656-660
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    • 2004
  • The Mobile Mapping System is an effective method to acquire the position and image data using vehicle equipped with the GPS (Global Positioning System), IMU (Inertial Measurement Unit), and CCD camera. It is used in various fields of road facility management, map update, and etc. In the general photogrammetry such as aerial photogrammetry, GCP (Ground Control Point)s are needed to compute the image exterior orientation elements (the position and attitude of camera). These points are measured by field survey at the time of data acquisition. But it costs much time and money. Moreover, it is not possible to make sufficient GCP as much as we want. However Mobile Mapping System is more efficient both in time and money because it can obtain the position and attitude of camera at the time of photographing. That is, Indirect Georeferencing must use GCP to compute the image exterior orientation elements, but on the other hand Direct Georeferencing can directly compute the image exterior orientation elements by GPS/INS. In this paper, we analyze about the positional accuracy comparison of ground point using the Direct Georeferencing and Indirect Georeferencing.

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Accuracy Analysis of Combined Block Adjustment with GPS/INS Observations Considering Photo Scale (사진축적을 고려한 GPS/INS 항공사진측량 블록조정의 정확도 분석)

  • Lee Jae One
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.23 no.3
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    • pp.323-330
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    • 2005
  • More than ten years after the era of GPS-Photogrammetry which could provide us only three projection center of all six exterior orientation parameters, direct georeferencing with GPS/INS is now becoming a standard method for image orientation. Its main advantage is to skip or reduce the indirect ground control process. This paper describes the experimental test results of integrated sensor orientation with a commercial GPS/IMU system to approve its performance in determination of exterior orientation. For this purpose two different imaging blocks were planned and the area was photographed at a large photo scale of 1:5,000 and a medium photo scale of 1:20,000. From these data set a variety of meaningful results was acquired, i.e., the accuracy. potential of exterior orientation from direct georeferencing and combined block adjustment using these data considering different photo scales and conditions.

The Analysis Accuracy of Mapping using Direct Georeferencing (Direct Georeferencing을 이용한 도화 정확도 분석)

  • Song Youn-Kyung;Lee Jae-One
    • Spatial Information Research
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    • v.13 no.1 s.32
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    • pp.31-41
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    • 2005
  • In order to carry out aerial photogrammetry using GPS/INS, it is necessary to apply exterior orientation parameters, obtained while making a photo, to the editing process. It should be noted that the verification process of aerial mapping result is the most crucial process at the GPS/INS based digital photogrammetry. To this end, this study has compared the mapping result by the ways of AT results, plotter, and orientation, which is from basis of the Analytical raw map produced by the existing AT results. When comparing the horizontal and vertical accuracy of the analytical mapping with that of digital restitution, it could be found that the latter is more accurate than that of the former. In addition, it was reveled that the horizontal error was bigger than that of vertical one. Even though the accuracy of the GPS/INS based AT Direct orientation was three times poorer than the of indirect one, it was recognized that the photogrammetry process was effectively performed in the application of scale 1:5000 mapping with satisfying the allowance errors.

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Multi-camera System Calibration with Built-in Relative Orientation Constraints (Part 1) Theoretical Principle

  • Lari, Zahra;Habib, Ayman;Mazaheri, Mehdi;Al-Durgham, Kaleel
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.3
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    • pp.191-204
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    • 2014
  • In recent years, multi-camera systems have been recognized as an affordable alternative for the collection of 3D spatial data from physical surfaces. The collected data can be applied for different mapping(e.g., mobile mapping and mapping inaccessible locations)or metrology applications (e.g., industrial, biomedical, and architectural). In order to fully exploit the potential accuracy of these systems and ensure successful manipulation of the involved cameras, a careful system calibration should be performed prior to the data collection procedure. The calibration of a multi-camera system is accomplished when the individual cameras are calibrated and the geometric relationships among the different system components are defined. In this paper, a new single-step approach is introduced for the calibration of a multi-camera system (i.e., individual camera calibration and estimation of the lever-arm and boresight angles among the system components). In this approach, one of the cameras is set as the reference camera and the system mounting parameters are defined relative to that reference camera. The proposed approach is easy to implement and computationally efficient. The major advantage of this method, when compared to available multi-camera system calibration approaches, is the flexibility of being applied for either directly or indirectly geo-referenced multi-camera systems. The feasibility of the proposed approach is verified through experimental results using real data collected by a newly-developed indirectly geo-referenced multi-camera system.