• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.693-699
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• 2006

Digital airborne image must be precisely orthorectified to become geographical information. For orthorectification of airborne images, GPS/INS (Global Positioning System/Inertial Navigation System) and LIDAR (LIght Detection And Ranging) elevation data were employed. In this study, 635 frame airborne images were produced and LIDAR data were converted to raster image for applying to image orthorectification. To derive images with constant brightness, flat field correction was applied to images. The airborne images were geometrically corrected by calculating internal orientation and external orientation using GPS/INS data and then orthorectified using LIDAR digital elevation model image. The precision of orthorectified images was validated by collecting 50 ground control points from arbitrary five images and LIDAR intensity image. As validation result, RMSE (Root Mean Square Error) was 0.387 as almost same as only two times of pixel spatial resolution. It is possible that this automatic orthorectification method of airborne image with higher precision is applied to airborne image industry.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.251-258
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• 2007

Airborne Lidar (light detection and ranging) can be an effective alternative in forest inventory to overcome the limitations of conventional field survey and aerial photo interpretation. In this study, we attempt to develop methodologies to identify individual trees and to estimate tree height from airborne Lidar data. Initially, digital elevation model (DEM) data representing the exact ground surface were generated by removing non-ground returns from the multiple-return laser point clouds, obtained over the coniferous forest site of rugged terrain. Based on the canopy height model (CHM) data representing non-ground layer, individual tree heights are extracted through pseudo-grid method and moving window filtering algorithm. Comparing with field survey data and aerial photo interpretation on sample plots, the number of trees extracted from Lidar data show over 90% accuracy and tree heights were underestimated within 1.1m in average at two plantation stands of pine (Pinus koraiensis) and larch (Larix leptolepis).

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.3 s.33
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• pp.59-67
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• 2005

Building information is primary source in many applications such as mapping, telecommunication, car navigation and virtual city modeling. While aerial CCD images which are captured by passive sensor(digital camera) provide horizontal positioning in high accuracy, it is far difficult to process them in automatic fashion due to their inherent properties such as perspective projection and occlusion. On the other hand, LIDAR system offers 3D information about each surface rapidly and accurately in the form of irregularly distributed point clouds. Contrary to the optical images, it is much difficult to obtain semantic information such as building boundary and object segmentation. Photogrammetry and LIDAR have their own major advantages and drawbacks for reconstructing earth surfaces. The purpose of this investigation is to automatically obtain spatial information of 3D buildings by fusing LIDAR data with aerial CCD image. The experimental results show that most of the complex buildings are efficiently extracted by the proposed method and signalize that fusing LIDAR data and aerial CCD image improves feasibility of the automatic detection and extraction of buildings in automatic fashion.

• 한국지형공간정보학회:학술대회논문집
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• 2003.09a
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• pp.177-181
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• 2003

최근 고해상도의 영상과 컬러항공영상의 출현과 더불어 도심지역의 지물 지모에 대한 상세한 묘사가 가능해지고 있다. 하지만 도심지역의 지물 지모의 복잡성으로 인하여 지물의 추출이 쉽지 않다. 특히, 건물에 의한 가림, 그림자에 의한 정보 왜곡 등의 발생으로 지형정보 추출의 어려움을 겪고 있다. 건물에 의한 폐색은 다른 위치에서 촬영을 하므로서 보정을 할 수 있지만 그림자에 의한 영향은 촬영위치에 상관없이 항상 발생한다. 본 연구에서는 도심지역에서 촬영한 컬러항공사진에서 그림자에 의한 정보 왜곡을 LIDAR 자료와 수치지도를 이용하여 보다 자동화된 과정으로 처리하므로서 그 판독력을 증대시키고자 한다.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.20-27
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• 2012

The flowed soil volume is able to be estimated simply from topographic data of before and after the debris flow. However, it is often difficult to obtain high resolution topographic data before debris flow because debris flow was occurred in mountainous area and airborne Lidar data was mainly surveyed in urban area. For this reason, Woo(2011) developed the topographic restoration method that can reconstruct the topography before the debris flow using airborne Lidar data. In this study, we applied the topographic restoration method on Inje county, Bongwha county and Jecheon city, produced topography data before debris flow that RMSE is from 0.16 to 0.34 m. Also, a soil variation was analyzed by topography data before and after debris flow, and it was used to estimate a real soil volume flowed to downstream and a spatial distribution showing collapses, flows, sedimentations appeared to debris flow.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.281-286
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• 2005

여러 분야에서 활용성이 증가하고 있는 도시지역에 대한 3차원 모형화 구축은 기존에는 항공사진이나 고해상도 위성영상을 주로 활용하여 왔으나, 최근에는 높은 정밀도를 보장하는 항공LIDAR 측량기법에 대한 연구가 활발히 진행되고 있다. 특히, 다양한 형태, 크기, 종류의 건물들이 존재하는 광범위한 도시지역을 모형화 하기 위하여 정밀도가 높은 LIDAR 자료를 통하여 신속하고 정확하게 현실에 가까운 건물 모형으로 복원하는 기술 개발이 요구되고 있다. 본 연구에서는 LIDAR 관측자료 및 디지털 영상, 수치지도 등의 자료를 활용하여 LIDAR자료의 전처리 과정과 다양한 필터를 적용하여 지면과 비지면 정보를 분류하였으며, LoG 연산자에 의한 건물 경계선 및 특징점 추출기법을 개발하여 도시 지역의 3차원 건물 복원기법을 제안하였다.

• Journal of the Korean Geophysical Society
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• v.9 no.2
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• pp.87-97
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• 2006

LIDAR(Light Detection and Ranging) is a new technology for obtaining DEM(Digital Elevation Model)ewith high density and high point acuracy. As LIDAR emerged, DEM could be developed in the earthsurface more efficiently and more economically, compared to the conventional aerial photogrametry.In this study, a digital camera is simultaneously used in combined LIDAR surveying, and acquired digitial image and DEM produce digital orthoimage. In this process, methods of combining sensor andorthoimage, GCPs determined by GPS surveying are used. Two digital orthoimage are produced; onewith a few GCP and the other without them. The produced maps can be used to corect or revised1:1,000 or 1:5,000 scale maps acordingly.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.751-760
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• 2009

This research aims to develop the strategy and method to enhance the reliability of image matching results and improve the efficiency of the matching process by utilizing LIDAR data in the main image matching processes. In this work, we present the methods to utilize LIDAR data in the selection of matching entities, the search for the matched entities and the evaluation of the matching results. The proposed method has been applied to medium-resolution digital aerial images and LIDAR data acquired at the same time. The results have been analyzed in comparison with an existing method using a virtual horizontal surface rather than LIDAR DEM. This analysis indicates that the proposed method can show significantly more improved performance than the existing method. The results of this study can contribute to the improvement of the currently available commercial image matching software and the enhancement of the DEM derived from LIDAR data and matching results.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.2
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• pp.33-40
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• 2014

At present, Cadastral map of 2 dimensional is in the stream of changing it to 3 dimensional type supported by GPS and laser techniques. In addition, this steam can be explained at the same time with improvement of equipment of storing much information, support of equipment for imaginative 3D spatial information, and support of equipment of expressing land in 3D Cadastral. This study suggest to apply airborne lidar survey technique on cadastral map to acquire comparably and quickly detailed height of ground. For doing this, this study checked out credibility regarding accuracy of airborne lider survey. After choosing research area, this study has done the airborne lidar survey and acquire the result after surveying Cadastral Comparison Point to check out the accuracy of acquired results. In addition, this study check out the result of Cadastral Comparison Point and airborne lidar survey applied by paired sample t-test based on actual results. The result is that test statistics is 0.322 which is 5 % similar level and null hypothesis cannot be rejected, so this study found out that result of both survey ways are the same. Therefore, the result of airborne lidar survey can be utilized to build up 3D Cadastral information hereafter.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.265-268
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• 2008

Lidar(Light Detection and Hanging, Ladar)는 물체에 반사되어 되돌아오는 광학신호를 관측하여 물체와의 거리를 측정하는 센서로 정밀한 3차원 모델 생성 및 도시지역의 변화탐지 등에 효율적으로 적용될 수 있다. 시뮬레이션은 시스템의 동작을 인공적으로 만들어 내고, 이 동작의 실행을 관찰하여 실제 시스템의 특성을 추론하는 일련의 활동으로, 하드웨어의 설계 및 분석, 보완, 성능 평가 등에 효율적으로 이용된다. 본 연구에서는 Lidar 시스템의 원리 및 구조 분석을 통해서 Lidar 데이터를 시뮬레이션하기 위한 소프트웨어를 설계하였다. Lidar의 특성이 시뮬레이션 소프트웨어에 정확하게 구현되도록 하기위해 Lidar 동작과 관련된 내부 및 외부요소를 분석하고 기능에 따라 추상화하여 소프트웨어 모들로 구성하였다. 시스템 내부요소로 송신부 수신부 신호/영상처리부 모델과 외부환경요소로 비행환경 모델, 타겟 모델, 대기 모델을 정의하였다. 또한, Lidar 시스템 실행 중에 발생하는 주요 프로세스를 함수 모듈로 정의함으로서, 모델들 간의 구조적인 관계를 정의하였다. 본 연구의 설계결과는 이후 Lidar시뮬레이션 소프트웨어의 보다 체계적인 구현에 적용될 예정이다.