• Journal of the Korean Geotechnical Society
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• v.24 no.2
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• pp.59-65
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• 2008

Digital close-range photogrammetric technique can measure and describe 3D geometric farm from 2D image. This technique is increasingly applied in the field of sciences. In the fields of civil and mechanical engineering, which need precise measurements for design, expensive measuring equipments are widely used. In occasions where visual inspection is required in addition to other forms of measurements, appropriate measuring equipments have not been yet available. This study utilizes digital close-range photogrammetric technique to quantitatively analyze behavior patterns before and after destruction from test model of reinforced-soil wall. Then the results are compared with the measurements obtained using digital theodolite to verify the reliability of the proposed method.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.151-160
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• 2004

This research addresses the experimental application of the digital close-range photogrammetric technique for 3D deformation measurement and visualization of road slope. The 3D displacements were extracted by the photo-triangulation based on the bundle adjustment method using the digital imagery. In addition, we produced the digital elevation models, the digital orthorectified images and the 3D perspective view images of the slope employing a digital photogrammetric workstation. Also the inclination map of the slope was generated as the data for monitoring and managing dangerous slopes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.4
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• pp.323-331
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• 2008

Digital close-range photogrammetric technique can measure and describe 3D geometric form from 2D image. This technique is a growing applicability in the field of sciences. Nevertheless, civil and mechanical field, which need measurements as precise as possible, use expensive measuring instruments in general. In addition there are occasions for analysis by means of visual method, since appropriate measuring instruments have been not yet available. This study therefore developed digital close-range photogrammetric technique with a movable orientation board to quickly measure deformation before and after destruction from simulated ground model of reinforced-soil wall. Then the results are compared with the measurements obtained using digital theodolite.

• Journal of Korean Society for Geospatial Information Science
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• v.7 no.2 s.14
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• pp.143-153
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• 1999

GIS have become easier to use and very popular. In recent year digital photogrammetric systems ire becoming cost-effective tools to build and update GIS databases. In close-range photogrammetry for the acquisition of geospatial data, the bundle adjustment needs both initial approximate values and control points to solve the exterior orientation parameters. This paper gives a review of applied and potential algorithms for estimating Initial approximate values before the bundle adjustment, develope new algorithms for determine the exterior orientation parameters, and gives a cost-effective methods for close-range digital photogrammetric system Modifications of existing DLT algorithm were made in this study for providing an efficient, economic, and more accurate photogrammetric data reduction technique. These modifications include robust approaches for automatic detection and elimination of all lands of gross errors in the measurement data, and incorporation of GPS to reduce the number of control points necessary for a DLT solution. Also, this paper derives a new method for space resection from a monocular image. A major advantage of proposed method is that the solution can be uniquely and analytically determined without initial approximate values of exterior orientation parameters and without iterative computation.

• Korean Journal of Geomatics
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• v.3 no.1
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• pp.43-51
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• 2003

This paper presents the benefits of using close-range digital photogrammetric techniques for measuring the roughness of rock surfaces, using digital stereo images obtained from a Rolleiflex 6006 metric camera. To precisely measure surface roughness, we researched on how to use the flat and curved reference surface obtained from geometrically corrected digital images of the rock surface by using the least squares method. To test the precision of the proposed technique, the surface roughness has been measured between the reference surface and sample areas of very smooth-surfaced rock. Then the results were compared with the measurements obtained from a laser sensor profilometer.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.2
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• pp.135-141
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• 2000

This study aims to analyze stone's surface roughness measurement accuracy of a high resolution DCS 420 digital camera by digital close-range photogrammetric technique. For this purpose, the surface roughness measurement system was constructed by means of microsoft visual basic 6.0 in windows. As the analysis results of measurement accuracy of digital camera using this system, the roughness error of the normal distance between the best fitting reference surface obtained by least square method and sample points in the ideal plane or surface did not exceed $\pm$0.1 mm

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.199-208
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• 1995

Significant developments in the use of digital imagery for close-range photogrammetric metrology have occured in the last few years because of technological advances in digital image processing. Present day needs for applications of digital image processing technique to measurements of photographs obtained with non-metric camera at reduced cost, automation and convenience. In order for this application to be useful, a detailed procedure must be developed. Investigation of this study is given to the detailed procedure for the digital measurements of the object space data from the scanned non-metric photographs.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.711-721
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• 2009

This study proposed digital close-range photogrammetric technique to measure deformation of I-plate-girder bridge. To compare deformation-measurement using the proposed method, a loading tester is used in the same time. As results, deviations of measuring values between the two methods range from 1mm to 2mm, and we could find-out simultaneously deflection and torsion of I-plate girder by repeated load of train. Then this study verified a measuring feasibility of I-plate-girder deformation by the proposed method. This may be alternative method of precise-stability inspection and manpower inspection.