• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2009.04a
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• pp.295-296
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• 2009

국내에 도입된 라인센서방식의 디지털항공카메라 ADS40영상을 활용하여 항공삼각측량을 수행하는데 있어 기준점의 수량 및 배치를 달리하여 성과를 분석한 결과는 모든 방법에서 국토지리정보원 항공사진측량작업내규에서 요구하는 정확도를 확보할 수 있었고, 기준점의 배치가 조밀하면 좀 더 양호한 성과를 확보할 수 있음을 확인했다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.397-405
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• 2015

Currently, Korea's digital maps are being produced through traditional aerial photogrammetry methods. Aerial photogrammetry is the most economical way to produce a map of a wide area. However, timely survey is not allowed depends on weather condition and it is inefficient for small area surveying in economic point of view. Therefore, it costs too much and needs long time to produce a map for various small areas where are terrestrial changes for updating the map. In contrast, UAV photogrammetry is possible to work even in cloudy weather because of shooting at low altitude below the clouds. It also has excellent mobility and shoot quickly and well suited for small-scale mapping in several places by low cost. In this study, we produced an ortho-photo and digital map with the UAV photogrammetry method using SIFT and SfM algorithm and verified its accuracy to evaluate the applicability for future digital map updates. The accuracy was verified by comparing the results of the ground survey for check points selected on the digital map. Test results show small errors at ±2.6cm in X coordinates, ±2.8cm in Y coordinates and ±5.8cm in height and we could find a possibility that UAV photogrammetry would be fully applicable for digital map updating.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.4
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• pp.355-362
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• 2017

Recently, UAV(Unmanned Aerial Vehicle) have been utilized in various fields, including surveys, mapping, and spatial analysis, depending on the increase in demand for spatial information and UAV is receiving a lot of attention due to rapid data acquisition and economic viability. In this study, the applicability of UAV image images was analyzed for urban disaster prevention. UAV images were acquired for the study area and digital surface model and ortho image were generated through data processing. Also, the process using PPK(Post Processed Kinematic) GNSS method is compared with existing method. Through the research, it was able to effectively deploy urban disaster prevention information about the target area, and displayed the effectiveness of the methods for efficient comparison with existing unmanned aerial photogrammetry. If the PPK technique is applied to thethe disaster prevention field, it is expected that the work flow in the field of rapid data acquisition and disaster prevention data construction can be greatly improved.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.449-454
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• 2010

Lately, airborne digital camera and airborne laser scanner in field of airborne surveying are used to build geography information such as digital ortho photo map and DEM(Digital Elevation Model). In this study, 3D position accuracy is compared medium format CCD camera RCD105 with airborne digital camera DMC. For this, test area was decided for aerial photograph. And using 1/1,000 scale digital map, ground control points were selected for aerial triangulation and check points were selected for horizontal/vertical accuracy analysis using softcopy stereoplotter. Accuracy of RCD105 and DMC was estimated by result of aerial triangulation and result of check points measurement of using softcopy stereoplotter. In result of aerial triangulation, RMSE(Root Mean Square Error) X, Y, Z of RCD105 is 2.1, 2.2, 1.3 times larger than DMC. In result of check point measurement using softcopy stereoplotter, horizontal/ vertical RMSE of RCD105 is 2.5, 4.3 times larger than DMC. Even though accuracy of RCD105 is lower than DMC, it is maybe possible to make digital map and ortho photo using RCD105.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.115-120
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• 2009

Point-based methods with experienced human operators are processed well in traditional photogrammetric activities but not the autonomous environment of digital photogrammetry. To develop more robust and accurate techniques, higher level objects of straight linear features accommodating element other than points are adopted instead of points in aerial triangulation. Even though recent advanced algorithms provide accurate and reliable linear feature extraction, extracting linear features is more difficult than extracting a discrete set of points which can consist of any form of curves. Control points which are the initial input data and break points which are end points of piecewise curves are easily obtained with manual digitizing, edge operators or interest operators. Employing high level features increase the feasibility of geometric information and provide the analytical and suitable solution for the advanced computer technology.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.31-31
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• 1995

TIN은 Triangulated Irregular Network의 약자로 불규칙한 대소삼각형의 집합으로 삼각망을 구성, 지표면을 Digital Terrain Model로 만드는 기법이다. 지표면(해저지형포함)은 수치화된 등고선의 벡터 데이터와 점의 표고데이터 또는 표고 평행배열의 Raster데이터로부터 모형화되며 또는 제 3의 방법인 TIN에 의해 모형화된다. 이 TIN에 의한 도형은 컴퓨터가 위성측량, 항공측량, 광파측량 또는 음차수심측량등 측량결과를 받아 어떤 특정 프로그램을 구동 삼각형의 정점에 해당하는 점의 X, Y, Z의 좌표로부터 닫한 삼각형을 작성한다. (중략)

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.545-553
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• 2009

Digital Elevation Models (DEM) is widely used in establishing the topographic profile in nation spatial information. Aerial Light Detection And Ranging (LiDAR) system is one of the well-known means to produce DEM. The system has fast data acquisition procedures and less weather-dependent restrictions compared to photogrammetric approaches. In this regards, LiDAR has been widely utilized and accepted in the process of nation spatial information generation due to its sufficient positional accuracy. However, the investigation of the accuracy of aerial LiDAR data over the area of forestation with various kinds of vegetations has been barely implemented in Korea. Hence, this research focuses on the investigation of the accuracy of aerial LiDAR data over the area of forestation and the evaluation of the acquired accuracy according to the characteristics of the vegetations. The study areas include land with shrubs and its adjacent forest area with mixed tree species. The spots for the investigation have been selected to be well-distributed over the whole study areas and their coordinates are surveyed by Global Positioning Systems (GPS). Then, the surveyed information and aerial LiDAR data have been compared with each other and the result accuracy has been evaluated. Conclusively, it is recommended that LiDAR data collection to be conducted after defoliation period, especially over the areas with broadleaf trees due to the possibility of significant outliers.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.345-345
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• 2020

우리나라는 물산업 강국 도약을 위한 글로벌 경쟁력을 갖추기 위해 2015년 세계물포럼 이후 복합 수재해 대응과 능동적 하천관리 분야가 중요시되고 있다. 기존의 하천관리는 수위관측소 및 하도계획을 중심으로 이루어져왔으나 최근에는 항공측량, 드론 등 원격관리시스템에 기반을 둔 하천 통로에 대한 입체적인 3차원 관리로의 인식 전환이 고려되는 추세이다. 대부분 수위 및 하도를 중심으로 한 조사방식은 계측장비, 인력, 시간 등 많은 소요비용이 필요하게 되어 급변하는 하천 공간 조사 기술로 제한적 요소가 많아 현재의 하천조사 시스템으로는 하천관리에 필요한 데이터를 환경변화에 맞추어 신속하고 정확하게 취득하기가 어려운 실정으로 하천관리 고도화를 위해 필요한 자료를 적기에 신속하고 효율적으로 구축할 수 있는 기술 개발 필요한 실정이다. 사회 환경의 발달로 급변하는 환경에 맞는 적정한 하천관리를 위해서는 유역 및 하천에 대한 수문정보 생산 및 하상변동조사가 필요하고 첨단기술(ICT)을 활용하여 조사의 효율성, 안전성 및 정확성을 높일 필요성이 있다. 한편, 하천유역조사는 하천유역에 대한 다양한 정보 수집을 목표로 하나 그간 유역조사에 대한 체계적인 연구가 이루어지지 않아 수요자의 요구 자료 제공이 미흡한 실정이다. 최근 수심, 하상, 하천재료 등 하천법에 규정된 측량은 현장 직접계측을 통해 실시되고 있으며 측량의 공간적·시간적 범위의 변동으로 기존 방식의 비용이 급증하게 되어 신기술을 통한 효율화가 필요한 실정이다. 현재 하천조사를 위해 위성 및 유인항공기 등 다양한 방법이 활용되고 있으나 고빙용을 수반하고 위성영상은 공간해상도가 낮아 폭이 좁은 하천에 적용하는데 한계가 있다. 또한, 폭이 좁고 길게 형성된 하천의 특성상 항공측량 보다 드론이 효율적으로 드론에 레이저 광선으로 지형을 측량하는 장비를 탑재해 3차원 지형을 측량하는 방법이 유리하다. 따라서 본 연구에서는 동진강 상류 하천을 대상으로 드론을 활용할 경우 투입인력 및 소요시간 절감, 장비 및 인력 진입 불가지역에 대한 정보획득, 높은 공간해상도, 항공측량 대비 경제성이 높은 것으로 판단되어 드론을 활용하여 하천지형 모니터링을 실시하여 유역관리 및 수질모델링에 필요한 지도 생성 및 유역의 공간 정보를 획득하여 향후 유역관리 모형의 기초자료로 활용하고자 하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.437-444
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• 2008

In the paper, a methodology is verified to integrate IKONOS-2 satellite imagery and ALS dataset by compensating biases of RPC models. To achieve this, conjugate features from both data should be extracted in advance. For this purpose, linear features are chosen as conjugate features because they can be accurately extracted from man-made structures in urban area and more easily extracted than point features from ALS data. Then, observation equations are established from similarity measurements of the extracted features. During the process, several kinds of transformation functions were selected and used to register them. In addition, it was also analyzed how the number of linear features used as control features affects the accuracy of registration results. Finally, the results were evaluated by using check-points obtained from DGPS surveying techniques and it was clearly demonstrated that the proposed algorithms are appropriate to integrate these data.

• Spatial Information Research
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• v.12 no.2
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• pp.181-191
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• 2004

Nowadays, GPS-photogrammetry can be applied to the basemap production, a land register and NGIS. And from now on, as the increase of GPS receiver rate, the study on the interpolation methods considering the exact movement of an aircraft at photoflight and the study on the supplement of GPS defect by INS are required continuously. GPS-Photogrammetry, which are based on the direct measurement of the projection centers and attitude at the moment of camera exposure time through loading the GPS receiver in aircraft. This photogrammetric methods can of for us to acquire the exterior orientation parameters with only minimum ground control points, even the ground control process could be completely skipped. Consequently, we can drastically reduce the time and cost far the mapping process. In this thesis, two test flights were conducted in area to evaluate the performance of accuracy and efficiency through the analysis of results between the two photogrammetric methods, that is, traditional photograrammetry, GPS-Photogrammetry. Test results shows that a large variety of advantages of GPS-Photogrammetry against traditional photogrammetry is to be verified. Especially, the number of ground control points for the exterior orientation could be saved more than 70～80%, and the cost far map production 30～50%, respectively. In addition, it was convinced that the large reduction of control points has not any effect on the block accuracy.