• 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 Association of Geographic Information Studies
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• v.8 no.3
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• pp.55-64
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• 2005

This study demonstrates the experiment based on digital photogrammetric processing for acquiring data related to slope monitoring. To apply dose-range digital photos for monitoring road rock slopes, digital elevation models and digital orthophotos were generated and 3D modelling was conducted for the visualization on a digital photogrammetric workstation. These digital photogrammetric products can be utilized as objective and scientific data not only for surveying and analyzing the shape and characteristics of the slopes but also for extracting various engineering data for building the database of the slopes and making the safety diagnosis of the slopes.

• 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.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.257-264
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• 1999

The lens distortions were corrected directly using the high-order polynomial which was offered in camera calibration data for the forward transformation and the root of Newton-Raphson's $2\times{2}$ nonlinear system for the backward transformation. The 0.04~0.08 pixels increase in accuracy was indicated through the use of direct correction of lens distortions instead of least square methods of commercial software. The least square adjustment method of high-order polynomial requires many control points which has a same weight. But this suggested method which is unnecessary to determine control points was developed and applied. The algorithm showed improved efficacy.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.2
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• pp.69-77
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• 1993

Investigation is given to the detailed procedure of a computer assisted automatic correction for scanning errors of the digital images of close-range photographs scanned by the CCD camera scanner. After determination of the exterior orientation parameters, photo coordinates of the all pixels were calculated using collinearity equation. For the generation of geometric corrected image from the photo coordinates of the all pixels, inverse-weighted-distance average method was used. And the accuracy of the resulting new image was checked comparing its image coordinates with there corresponding ground coordinates for the check points.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.389-394
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• 2004

Structure-typed cultural heritage, objects of preservation are positioned as one of the very important heritage in the nation, and the preservation of prototypical structures become influential in national development and against natural disaster. For this reason, Digital Close Range Photogrammetry has recently been diversely used. Despite its popular use, the measurement has limits that make it unsuitable for photographing precise cultural heritage situated at high mountainous terrain or where people can not approach easily. These high gigantic stone statues are among the preserved structure-typed cultural heritage. In order to supplement the limits, when using the measurement, a camera tripod with +30m, a ladder truck and a shore should be equipped, which means additional equipment leads to it being a waste of cost and time. In this vein, a device was developed in detail, using a RC Helicopter installed with a CCD video camera with ease of control, safety, equipment, carrying, movement and approach, then checked image shot by a wireless modem at real time and considered the economical efficiency without re-photographing. Next, the author digitized the images of the nationally designated structure-typed cultural heritage, used materials on their restoration as the third dimension in order to construct the integrated management-information system for cultural heritage. Through the above processes, this study can provide specific information on 3D images and 3D CAD sections of structured-typed cultural heritage for both the public and specialists on the web. Moreover, it suggests the foundation to restore the damaged cultural heritage in the future by aiming for their effective management and preservation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.4
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• pp.321-330
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• 1999

Automation of observation and positioning of fiducial marks is made possible with the application of image matching technique, developed through the cooperative research effort of computer vision and digital photogrammetry. The major problem in such automation effort is to minimize the computing time and to increase the positional accuracy. Except for scanning and ground control surveying, the interior orientation process was automated in this study, through the development of an algorithm which applies the image matching and image processing techniques. The developed system was applied to close-range photogrammetry and the analysis of the results showed 54% improvement in processing time. For fiducial mark observation during interior orientation, the Laplacian of Gaussian transformation and the Hough transformation were applied to determine the accurate position of the center point, and the correlation matching and the least squares matching method were then applied to improve the accuracy of automated observation of fiducial marks. Image pyramid concept was applied to reduce the computing time of automated positioning of fiducial mark.

• 한국지형공간정보학회:학술대회논문집
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• 2003.09a
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• pp.207-210
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• 2003

본 연구에서는 측량용 디지털 카메라인 Rollei사에서 제조한 d7 metric과 d7 $metrics^5$를 이용하여 촬영거리와 수렴각을 4m와 $30^{\circ}$로 일정하게 유지하고, 촬영방향을 다르게 하여 촬영하였으며, 또한 표정장업 시 일어나는 오차를 최소화 하기 위해 프로그램상에서 자동적으로 상호표정이 되는 원형타켓을 사용하였으며, 광속조정법을 실시하여 RMSE를 산출하였다. 이러한 연구는 근접사진측량으로 대상물을 측정할 시 촬영여건이 불가피하게 대상물의 중심방향에서 촬영이 어려울 경우 정확도를 평가하는데 이용될 것이라 사료된다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.5
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• pp.551-560
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• 2014

Compare to other industrial sites, the civil construction work not only takes longer time but also has made of complicated processes, such as the integrated management, process control, and quality control until the completion. However, it is hard to take control the construction sites, since numerous issues are always emerged. The study purposes on providing the dataset to synthetically manage and monitor the civil construction site, main design, drawings, process, construction cost, and others at real-time by using the low altitude close-range aerial images, based on UAV, and the GPS surveying method for treating the three-dimensional spatial information quickly and accurately. As a result, we could provide the latest information for the quick decision-making following from planning to completion of the construction, and objective site evaluation by the high-resolution three-dimensional spatial information and drawings. Also, the present map, longitudinal map, and cross sectional view are developed to provide various datasets rapidly, such as earthwork volume table, specifications, and transition of ground level.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.1 s.31
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• pp.3-10
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• 2005

This study attempts to measure effectively three dimensional deformation in road slopes using digital close-range photographs. After the still video images were acquired respectively on the same multi-station geometric configuration in two epoches, photo-triangulation was rallied out respectively by conventional standard bundle adjustment and free-net bundle adjustment and the computed results were compared with those of geodetic method by total station. Three dimensional coordinates and deformation amounts were able to be derived with the RMSE of sub-millimeter and the relative accuracy of $1/30,000{\sim}1/35,000$. It was shown that free-net bundle adjustment is about 13% higher than standard bundle adjustment in the accuracy of photo-triangulation. It was ascertained that the free-net technique is able to promote fast and accurate deformation surveying without the necessity of geodetic control survey in complicated industrial sites.