• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.183-190
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• 2007

To make use of surveying data obtained from different sensors and different techniques, it is a pre-requite step that register them in a common coordinate system. For this purpose, we developed methodologies to register IKONOS-2 Satellite Imagery using LiDAR(Light Detection And Ranging) data. To achieve this, conjugate features from these data should be extracted in advance. In this study, linear features are chosen as conjugate features. Then, to register them, observation equations are established from similarity measurements of the extracted features and the results was evaluated statistically. The results clearly demonstrate that the proposed algorithms are appropriate to register these data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.423-427
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• 2010

현재 GPS/INS 운영 방법은 일정한 범위 내에 GPS 지상기준국을 설치하도록 되어있다. 그러나 촬영지역이 넓을 경우나 작업의 우선순위 등에 따라 지상기준국의 운영이 곤란한 상황이 발생할 수 있으며, 작업자의 실수, 수신기의 오류 등으로 지상기준국을 항상 안정적으로 운영하기 어렵다. 이에 본 연구에서는 국토지리정보원의 GPS 상시관측소를 활용하여 항공레이저측량 원시자료를 구축하고, 지상 기준국을 사용한 결과와의 비교를 통해 기준국이 항공레이저측량 결과에 미치는 영향을 분석하고자하였다.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.4 s.38
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• pp.37-44
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• 2006

To use surveying data obtained from different sensors and different techniques, it is a pre-requite step that register them in a common coordinate system. For this purpose, we developed methodologies to register airborne photos, ALS (Airborne Laser Scanning) data and digital maps. To achieve this, conjugate features from these data should be extracted in advance. In this study, linear features are chosen as conjugate features. Based on such a selection strategy, a simple and robust algorithm is proposed for extracting such features from ALS data. Then, to register them, observation equations are established from similarity measurements of the extracted features and the results was evaluated statistically. The results clearly demonstrate that the proposed algorithms are appropriate to register these data.

• 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.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.61-70
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• 2005

Airborne laser scanning system needs preprocessing which removes some objects such as buildings from the raw DSM data to construct DEM in building area because the laser pulse can't penetrate into the buildings. This study applied the mean filtering method which has various size filter to the DSM data constructed by airborne laser scanning system and decided the optimal filter size as $39{\times}39$ by analyzing the standard deviation change ratio. Also, this study could get the ${\pm}0.065m$ standard error by comparing the optimal filtering DEM and DSM raw data of airborne laser scanning. Therefore, it could know that the mean filtering method, which is presented in this study, is very effective to extract DEM in the urban area which has a low relief.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.4
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• pp.359-365
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• 2011

This study aims at filtering ALS points into ground and non-ground effectively through labeling and window based algorithm by utilizing 2D adjacency based on scan line. Firstly, points adjacency is constructed through minimal search based on scan line. Connected component labeling algorithm is applied to classify raw ALS points into ground and non-ground by utilizing the adjacency structure. Then, some small objects are removed by morphology filtering, and isolated ground points are restored by IDW estimation. The experimental results shows that the method provides good filtering performance( about 97% accuracy) for diverse sites, and the overall processing takes less time than converting raw data into TIN or raster grid.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.95-106
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• 2003

This study evaluated the architectural density of urban district using airborne laser scanning(ALS) that is a method used in urban planning, water resources and disaster prevention with high interest recently. First, digital elevation model(DEM) and digital surface model(DSM) was constructed from Light detection and ranging(LiDAR). For getting the height of building, ZONALMEAN filter was used in DEM and ZONALMAJORITY filter was used in DSM. This study compared the floor from filtering with the floor from survey and got standard error, which is ${\pm}0.199$ floor. Also, through the overlay and statistical analysis of total-area layer and zone layer, we could present floor area ratio by zone. As a result of comparison with floor area ratio between airborne laser scanning data and survey data, the standard error of floor area ratio shows ${\pm}2.68%$. Therefore, we expect that airborne laser scanning data can be a very efficient source to decision makers who set up landuse plan in near future.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2001.10a
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• pp.147-151
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• 2001

본 연구에서는 항공 레이저 지형 매퍼(Airborne Laser Terrain Mapper 혹은 간단히 ALTM)을 이용하여 제작된 DTM의 정확도 분석을 위해 500m 간격으로 측점지역을 선정하고 검증 측점의 GPS 측량을 실시하여 다양한 방법을 통해 정확도를 검증하였다. ALTM의 DTM 각 점 사이의 고도 값 추정을 위해 TIN을 제작하고, GPS를 이용한 측점들의 커버리지를 제작하여 TIN과 중첩한 다음 정확도를 분석하는 방법과 GPS 측점 주변에 분포하는 DTM 자료를 평균하여 RMSE를 구하는 방법을 병행하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.33-42
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• 2003

As airborne laser scanning technique is developed with high vertical accuracy recently, there come many studies on DEM(digital elevation model creation, building extraction, flood risk mapping and 3D virtual city modeling. This study applied point comparative method, contour comparative method and digital map with scale 1/5,000 to calculate RMSE of DEM in according to resolution that was constructed using rawdata being acquired by airborne laser scanning. As a result, point comparative method showed lower DEM standard error than contour comparative method, it is a reason that contour comparative method was not carried out detailed grid calculation for point comparative method. Also, digital map with scale 1/5,000 showed higher DEM standard error than point comparative method and contour comparative method in below 25.4m that is average horizontal distance among contour line, and showed similar result with contour comparative method in over 25.4m.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.06a
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• pp.48-53
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• 2004