• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.177-186
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• 2009

Nowadays, as going to information society based knowledge, the informations are acquired, processed, serviced based digital environment. In surveying field, the trend have been changed from the analog foundation to the digital foundation. Also, aerial photogrammetry is being changed from analog aerial photogrammetry to digital aerial photogrammetry. In this paper, the analysis of accuracy is performed for the comparison of traditional aerial photogrammetry with digital aerial photogrammetry usign UltracamX in AT and Block Adjustment. As the results, Bundle adjustment in digital aerial photogrammetry with GPS/INS have more advantages than traditional independent adjustment in analog aerial photogrammetry. Digital aerial photogrammetry contributes the higher accuracy in AT and block adjustment more than analog aerial photogrammetry.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.743-750
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• 2009

Since aerial photogrammetry by analog camera began in 1972, recently, high resolution digital camera is actively introduced to improve efficiency of aerial photogrammetry. This study investigated the 3D positioning accuracy of DMC(Digital Mapping Camera) among various high resolution aerial digital cameras to be developed for photogrammetry. For the research, we installed control points in test field around Incheon, and acquired analog and digital aerial photographs. By comparing 3D positioning accuracies of analog and digital photographs, there are few difference between two cameras, and the 3D positioning accuracies of two cameras was somewhat increased in case of aerotriangulation using additional control points based on GPS/IMU EO data.

• Spatial Information Research
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• v.10 no.2
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• pp.317-329
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• 2002

Coastal landforms such as sand beach and coastal sand dune are changing dynamically, and the research about them is being conducted. Conventionally the leveling method has been applied to measuring heights of dynamic morphological surface in coastal landforms. We applied the photograrmmetric method which was not considered to measure the heights on coastal sand dune’s profile to calculating the heights of coastal sand dune; that is, the heights of unknown points on coastal sand dune’s profile was reckoned from the digital photographs’stereo pairs through bundle adjustment and backward transform of collinearity condition equation. we used six GCPs to perform bundle adjustment. After backward transform the error of heights between surveyed value and computed value was estimated around 10cm. In general, the pole is not adamantly fixed on the surface of coastal sand dune because of its softness, and then the disturbance of coastal sand dune adjoining surveyed area can be made in small area. Digital photogrammetry can solve the problem which conventional leveling method has, and be replaced it.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.438-448
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• 2012

Applicability of the digital photogrammetry technique for measurement of rock joint roughness is addressed in this study using the DSLR camera. Measurements of roughness were performed for two rock joint specimens using the laser profiler and the digital photogrammetry technique. The statistical roughness parameters were estimated for two dimensional roughness profiles constructed from each method. Obtained results showed that the statistical roughness parameters estimated from the digital photogrammetry technique were lower than that based on the laser profilometer, even though a high degree of correlation might exist between them. The effects of camera direction on roughness measurements were found to negligible in practice. The digital photogrammetry could be a cost effective method to measure the roughness of rock joints with various scale at the fields.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.663-668
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• 2010

In this study a stereo digital camera system was developed. Using this system, we can collect informations such as coordinates, lengths of all objects shown in the photo image just by taking digital photograph in field. This system has the advantage of obtaining stereo images with settled exterior orientation parameters, while the accuracy slightly worsen because in a close range photogrammetry with stereo digital camera system, the base line distance is restricted within about 1m. We took images with various exposure distances and angles to objects for experimental error assessment, and analyzed the affection of image coordinates errors.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.2
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• pp.91-99
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• 2009

In the field of geospatial information, 3D shape information has been considered as a frame data for GIS. Many kind of physical shape information is, especially, required for the works related with space, such as planning, maintenance, management, etc. Conventional photogrammetry was implemented under the conditions with expensive metric cameras and analytical plotters operated by experts. Nowadays, however, the metric cameras and analytical plotters are replaced by low price non-metric digital cameras and personal computers by virtue of the progress in digital photogrammetry. This study aims to investigate the technology to easily and promptly produce 3D shape information required in geospatial information system using close-range photogrammetry with non-metric digital cameras. As the results of this study, 3D shape of an experimental object was made out with a common compact digital camera and only a known length of a line component in the object and the accuracy of the dimension of 3D shape was analyzed to be less than one pixel.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.383-383
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• 2015

하천의 하상고 측량은 하상변동 분석, 서식처 구조 등을 이해하는데 매우 중요한 정보를 제공한다. 하지만, 현재까지 대부분의 하상고 측량은 일정한 간격의 하천 단면 측량에 의해서 행해져 왔다. 최근 GPS와 다중 빔 측심기를 이용하여 하상의 3차원적 형상을 조밀하게 측량하고 있으나 비용이 많이 들기 때문에 긴 하천 구간을 전부 측량하지는 못하고 특정한 부분에 대해서만 집중하고 있다. 항공 LiDAR의 경우 넓은 지역에 대해 신속하고 고해상도로 지형을 측량할 수 있으나 수중 투과 장비가 고가이며, 일반 적색 레이져 기반 LiDAR는 수중을 측정하지 못하여 하상 측량에 한계가 있다. 이에 대한 대안으로 활용할 수 있는 방법은 광학 기반의 원격 탐사에 의한 수심 측량 방법이다. 이 방법은 얕은 수심의 하천에 대한 활용되었는데, 광학 센서 이미지나 항공사진 등을 이용한다. 본 연구에서는 저고도에서 촬영한 고해상도 디지털 항공사진을 이용하여 모래하천의 수심을 추정하였다. 이 방법은 항공사진의 적색 및 녹색 색상값과 현장에서 정밀한 측위 하에 측량한 수심값 사이의 관계를 이용한다. 이를 통해 보정식을 수립하고 검사 자료를 이용하여 검증한 후 항공사진의 해당 지역에 대해 수심 부분을 마스킹 처리하여 하상고를 구축하였다. 검사 자료에 대한 RMSE는 약 12 cm로 나타났다. 이를 활용하여 대상 구간의 3차원적 지형 형상을 구축하였다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2000.10a
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• pp.40-50
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• 2000

본 연구에서는 Rolleiflex 6006 측정용 카메라로 촬영된 사진과 DCS 420 디지털 카메라로부터 촬영된 화상을 이용, 수치근접사진측량을 실시한 후, 조경석의 표면 거칠기 측정 정확도 향상을 위하여 최소제곱법으로 기준평면 또는 기준곡면을 찾아 사용하는 방법을 연구하였으며, 조경석 표면의 연마 이전과 연마 이후의 표면 거칠기를 측정, 비교하여 연마후의 거칠기 감소크기를 산출하고, 측정 정확도를 알아보기 위하여 거칠기가 거의 없는 평면인 돌과 곡면인 돌의 표면 거칠기를 측정한 결과, 그 거칠기를 기대정확도 이상인 각각 $\pm$0.lmm 및 $\pm$0.2mm의 정확도로 측정할 수 있었다. 또한 측정용 카메라인 경우 렌즈왜곡 보정에 있어서 검정자료를 토대로 기준점을 사용하지 않는 직접보정방법인 Newton-Raphson법을 적용하여 기하학적 정확도가 향상된 수치사진화상을 얻을 수 있었으며, DCS 420 디지털 카메라와 윈도우 운영체계인 Visual basic 6.0을 이용하여, 표면 거칠기 측정시스템을 구축함으로써 연마이전 조경석과 연마이후 조경석에 대한 표면 거칠기 및 형상을 정밀 측정할 수 있는 수치근접사진측량기법을 제시할 수 있었다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.10a
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• pp.133-137
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• 2002

• 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.