• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.271-276
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• 2006

Railroads made many contribution to modernization being developed so quickly as public transportation, but after middle of 20 century, its qualities are getting low because of focusing on the investment and development of cars and airplanes. Its role which is getting the excellent merits on the mass transportation, rapid transit. safety, state period, energy efficiency, and prevention of environmental pollution has been reconsidered. Element of horizontal alignment In an existing railroad line is needed as basic materials, when it will be improved or moved. If its design drawing was lost or damaged, it is impossible to recover. It is riot easy to repair for it as disasters. We must understand an existing railroad line to bring a function included a basic geography situation. In this studies we acquire, analyze. and handle the digital picture of railroads and then reappear shape of three dimension. But also we want to contribute to establish the facilities information choosing materials of existing railroad line in outputting the alignment element by reverse.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2005.11a
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• pp.59-80
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• 2005

This Paper Presents a Rational Function Model (RFM)-based image matching technique for IKONOS satellite imagery. This algorithm adopts the object-space approach and reduces the search space within the confined line-shaped area called the Piecewise Matching Line (PLM). Also, the detailed procedure of generating 3-D surface information using the Rational Function model Coefficients (RFCs) is introduced as an end-user point of view. As a result, the final generated Digital Elevation Model (DEM) using the proposed scheme shows a mean error of 2$\cdot$2 m and RMSE of 3$\cdot$8 m compared with that from 1:5000 digital map.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.10-18
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• 2001

The existing measurement system to ground-surface displacement survey of the slope has been including the hazard for the measure in site and the difficulty for install, maintenance and control of expensive instruments, which are impossible of whole survey on the slope surface. To overcome of those defects, Softcopy Photogrammertry method is used, which can measure displacement of ground-surface on the slope and structure deformation vectors. Recently, the survey methods applying the advantages of Photogrammetry and Digital Photogrammetry Survey are widely used. In this study, therefore, the development and application of the new instrument mechanism on the the site example are studied. Through the application of Softcopy Photogrammetry, the 3-D data of ground surface on the dangerous slope could be effectively obtained at the long distance, which are obtained through the reform process of contour line. Those are different to the results of the Close-Range Photogrammetry analysis. In ground instrumentation parts, the new practical system shall be the technical base to improve of the instrument machine as well as can be widely applied in civil engineering and others branch.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.1
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• pp.1-8
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• 2014

The positions, attitudes, and internal orientation parameters of three line scanners are critical factors in order to acquire the accurate location of objects on the ground. Based on the assumption that positions and attitudes of the sensors are derived either from direct geo-referencing which of using Global Positioning Systems (GPS) and Inertial Navigation Systems (INS), or from indirect geo-referencing which of using Ground Control Points (GCPs), this paper describes on biased effects of Internal Orientation Parameter (IOP) on the ground. The research concentrated on geometrical explanations of effects from different focal length biases on the ground. The Synthetic data was collected by reasonable flight trajectories and attitudes of three line scanners. The result of experiments demonstrated that the focal length bias in case of indirect geo-referencing does not have critical influences on the quality of reconstructed ground space. Also, the relationships between IO parameters and EO parameters were found by the correlation analysis. In fact, the focal length bias in case of the direct geo-referencing caused significant errors on coordinates of reconstructed objects. The RMSE values along the vertical direction and the amount of focal length bias turned out to be almost perfect linear relationship.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.363-368
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• 2012

The result of the line simplification algorithm varies with the choice of algorithms, the change in tolerance and the selection of target objects. Three of the algorithms used in this study are Sleeve-fitting, Visvalingam-Whyatt, and Bend-simplify. They were applied to the three kinds of objects which were buildings, rivers, and roads with the five degrees of the tolerance. Through this experiments the vector displacement, the areal displacement, and the angular displacement were measured and the qualitative analysis was performed with the trend line of the errors. The experimental results show that errors were differ from tolerance values, and characteristics of line simplification algorithms based on changes of tolerance were understood.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.11-17
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• 2000

GIS is the system that has ability of integrating, managing, and analyzing the voluminous graphic and text data, which is adequate system to manage complex network of the underground utilities of urban area. A development of gas line safety management system is accomplished to construct a database of gas line network and topographic data, create safety managing model, and estimate openly its safety by GIS. This system is designed to evaluate easily the damaged facilities in case of gas line explosion by the establishment of the geographic output system. It is designed to trace and present efficiently closed valves and interrupted facilities of gas when gas line breakage occurs, and offer the information by which one can take quickly emergency. And also, it is constructed to prevent from accident occurring under construction work by showing underground utilities and states of work.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.11-19
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• 1999

Lately, with the development of the fields of computer and photogrammetry, Digital Photogrammetric Systems are widely used for the generation of GIS basemap, the acquisition of topographic information and DEM, the formation of digital orthophoto, three-dimensional viewing and so on. According as the demand for the systems is rapidly increasing, we suggest keenly the necessity of domestic technical development, because all of these systems depend on foreign technology until now. In this study, by using digital photogrammetry method, with Visual C++ language, we have developed Digital Photogrammetric Systems for Windows which is able to get three-dimensional coordinates through interior orientation, exterior orientation, epipolar line, image matching from a pair of aerial photos taken with metric camera. This system consists of not only a module which can revise digital map that is being made at National Geographic Institute as a part of data construction project of National Geographic Information System, but also a module which can view three-dimensional image on the screen monitor by using anaglyph for three-dimensional analysis. The digital photogrammetry modules developed in this study are expected to be used as primary modules for the effective management of the urban as well as main modules in developing professional digital photogrammetric systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.151-159
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• 1992

In close-range photogrammetry, to employ non-metric camera especially for the purpose of precise measurement, systematic errors must, first of all, be corrected as they have a great influence on accuracies of results. For it, fiducial marks was built in non-metric camera and the factors such as PPS, PPA, EFL, CFL, and radial lens distortion coefficients for each quadrant were calibrated through collimator test. Also, the coefficients of both radial and tangential lens distortion were calibrated from analytical plumb line method and therefore main systematic errors could be effectively corrected. Using the calibrated non-metric camera, close-range photogrammetry could be successfully accomplished and accuracies could be improved sharply.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_1
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• pp.529-536
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• 2007

Registration between image and object space is a fundamental step in photogrammetry and computer vision. Along with rapid development of sensors - multi/hyper spectral sensor, laser scanning sensor, radar sensor etc., the needs for registration between different sensors are ever increasing. There are two important considerations on different sensor registration. They are sensor invariant feature extraction and correspondence between them. Since point to point correspondence does not exist in image and laser scanning data, it is necessary to have higher entities for extraction and correspondence. This leads to modify first, existing mathematical and geometrical model which was suitable for point measurement to line measurements, second, matching scheme. In this research, linear feature is selected for sensor invariant features and matching entity. Linear features are incorporated into mathematical equation in the form of extended collinearity equation for registration problem known as photo resection which calculates exterior orientation parameters. The other emphasis is on the scheme of finding matched entities in the aide of RANSAC (RANdom SAmple Consensus) in the absence of correspondences. To relieve computational load which is a common problem in sampling theorem, deterministic sampling technique and selecting 4 line features from 4 sectors are applied.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.33-40
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• 2000

The aim of this study is to extract bridge location(center line and width of a bridge) from SPOT XS data with 20. The boundary pixels were computed to get the mixture proportions of classes and this mixture proportions were used to extract center line and width of a bridge. The accuracy was tested by comparing the extracted bridge center line coordinate and width to the existing 1:5,000 scale national digital map and field survey data. The results of the comparison show that the measuring accuracy of the bridge center line coordinates and width are $\pm$2.9 m and $\pm$4.1 m.