지역난방에서의 급탕공급방식 비교검토

오재홍 대한설비공학회 1990 대한설비공학회 강연회 및 기타간행물 Vol.- No.-

Transmission Lines Rights-of-Way Mapping Using a Low-cost Drone Photogrammetry

오재홍,이창노 한국측량학회 2019 한국측량학회지 Vol.37 No.2

Electric transmission towers are facilities to transport electrical power from a plant to an electrical substation. The towers are connected using wires considering the wire tension and the clearance from the ground or nearby objects. The wires are installed on a rights-of-way that is a strip of land used by electrical utilities to maintain the transmission line facilities. Trees and plants around transmission lines must be managed to keep the operation of these lines safe and reliable. This study proposed the use of a low-cost drone photogrammetry for the transmission line rights-of-way mapping. Aerial photogrammetry is carried out to generate a dense point cloud around the transmission lines from which a DSM (Digital Surface Model) and DTM (Digital Terrain Model) are created. The lines and nearby objects are separated using nDSM (normalized Digital Surface Model) and the noises are suppressed in the multiple image space for the geospatial analysis. The experimental result with drone images over two spans of transmission lines on a mountain area showed that the proposed method successfully generate the rights-of-way map with hazard nearby objects.

신경 회로망을 이용한 화상인식에 관한 연구 ( A Study on Image Recognition Using A Neural Network )

오재홍,고형화 대한전자공학회 1989 대한전자공학회 학술대회 Vol.1989 No.1

제9회 가사ㆍ시조 창작 공모전 수상작품

오재홍,백점례,황정윤,황주현,박은선,전홍미,고동희,정영순,이정애,노정은,백미숙,박소담,류수정,김태훈,양새리,이승은,김정숙,강봉덕,허승자,김명운,조은영,이필은,이동원,이윤종,이은솔,정상석,권경림 고요아침 2008 시조시학 Vol.- No.-

아리랑3호 스테레오 영상의 에피폴라 기하 분석 및 영상 리샘플링

오재홍,서두천,이창노 한국측량학회 2013 한국측량학회지 Vol.31 No.6

Kompsat-3 is an optical high-resolution earth observation satellite launched in May 2012. The AEISSsensor of the Korean satellite provides 0.7m panchromatic and 2.8m multi-spectral images with 16.8km swathwidth from the sun-synchronous near-circular orbit of 685km altitude. Kompsat-3 is more advanced thanKompsat-2 and the improvements include better agility such as in-track stereo acquisition capability. Thisstudy investigated the characteristic of the epipolar curves of in-track Kompsat-3 stereo images. To this endwe used the RPCs(Rational Polynomial Coefficients) to derive the epipolar curves over the entire image areaand found out that the third order polynomial equation is required to model the curves. In addition, we couldobserve two different groups of curve patterns due to the dual CCDs of AEISS sensor. From the experimentwe concluded that the third order polynomial-based RPCs update is required to minimize the sample directionimage distortion. Finally we carried out the experiment on the epipolar resampling and the result showed thethird order polynomial image transformation produced less than 0.7 pixels level of y-parallax. 아리랑 3호는 2012년 5월 18일에 발사된 다목적실용위성으로서, 탑재된 AEISS센서는 고도 685km의 태양주기궤도상에서 0.7m의 공간해상도 흑백 영상과 2.8m 공간해상도의 다중 파장대 영상을 폭 16.8km로 획득한다. 아리랑 3호는 아리랑 2호에 비해 많은 부분에서 성능의 향상이 이루어졌으며 그 중 단일 패스에서 스테레오 영상이 취득 가능하도록 설계되었다. 아리랑 3호를 이용하여 3차원 지형 정보의 추출을 하기 위해서는 정확한 에피폴라 기하를 규명하는 것이 필수적이며, 따라서 본 연구에서는 아리랑 3호 스테레오 영상으로부터 에피폴라 영상 제작을위한 최적의 영상 변환식을 도출하기 위한 에피폴라 곡선의 특성에 대해 분석하였다. 영상과 함께 제공되는 RPCs(Rational Polynomial Coefficients)를 기반으로 영상 전역에 해당하는 에피폴라 커브를 도출하고 이에 대한 모양분석을 통해 에피폴라 커브가 최소 3차 다항식 이상의 변환식으로 모델링 될 수 있음을 알 수 있었다. 또한 아리랑3호 AEISS센서의 두 개의 CCDs라인 특징 또한 확인 가능하였다. RPCs 업데이트 시에도 샘플 방향의 영상 오차를 최소화하기 위해 3차식이 필요했으며, 에피폴라 영상 리샘플링 시에도 3차 영상 변환식을 활용한 경우 최대 0.7픽셀이내의 정밀한 y시차를 확보할 수 있었다.

역류방지에 대한 외국의 사례

오재홍,Leonard G. White 대한설비공학회 2001 대한설비공학회 강연회 및 기타간행물 Vol.- No.-

Direct Epipolar Image Generation From Ikonos Stereo Imagery Based On RPC and Parallel Projection Model

오재홍,신성웅,김경옥 대한원격탐사학회 2006 大韓遠隔探査學會誌 Vol.22 No.5

Epipolar images have to be generated to stereo display aerial images or satellite images. Pushbroom sensor is used to acquire high resolution satellite images. These satellite images have curvilinear epipolar lines unlike the epipolar lines of frame images, which are straight lines. The aforementioned fact makes it difficult to generate epipolar images for pushbroom satellite images. If we assume a linear transition of the sensor having constant speed and attitude during image acquisition, we can generate epipolar images based on parallel projection model (2D Affine model). Recent high resolution images are provided with RPC values so that we can exploit these values to generate epipolar images without using ground control points and tie point. This paper provides a procedure based on the parallel projection model for generating epipolar images directly from a stereo IKONOS images, and experimental results.

국토위성 3차원 데이터 생성을 위한 입체 기하 영상 생성 모듈 제작 및 테스트

오재홍,이창노 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.5

CAS500-1 and CAS500-2 are high-resolution Earth-observing satellites being developed and scheduled to launch for land monitoring of Korea. The satellite information will be used for land usage analysis, change detection, 3D topological monitoring, and so on. Satellite image data of region of interests must be acquired in the stereo mode from different positions for 3D information generation. Accurate 3D processing and 3D display of stereo satellite data requires the epipolar image resampling process considering the pushbroom sensor and the satellite trajectory. This study developed an epipolar image resampling module for CAS-500 stereo data processing and verified its accuracy performance by testing along-track, across-track, and heterogeneous stereo data. 국토관측 전용위성 (CAS500)은 국토 모니터링 및 관리를 위한 고해상도 위성영상 수요를 충족시키기위하여 개발 및 발사 예정 중인 고해상도 국토관측 위성이다. 해당 위성 데이터는 토지이용현황 분석, 변화탐지, 3차원 국토정보 분석 등 여러 응용분야에 활용 예정인데, 그 중 3차원으로 국토, 지형 정보를 생성하고 분석하기 위해서는 관심 지역을 서로 다른 두 방향에서 중복촬영을 통해 입체영상을 취득하고 이를 처리해야 한다. 특히 효율적이고 정밀한 3차원 정보 생성하거나 3차원으로 디스플레이 하기 위해서는 취득된 입체 영상을 정밀한 입체 기하 영상으로 변환하여 활용해야 하는데, 이때 푸쉬부룸 센서의 특성에 맞춘 에피폴라 기하를 적용하여 구현하여야 한다. 본 연구에서는 국토관측 위성 입체 데이터 처리를 위하여 입체 영상 생성 모듈을 구현하였고 단일궤도, 이종궤도, 이종영상 등의 테스트를 통해 정밀성을 분석하여 1픽셀 이내의 종시차를 확보할수 있음을 확인하였다.

Large Scale Topographic Mapping Using Stereo Pair Imagery from CAS500-1 Satellite

오재홍,지학송,양효진,황정인,이창노 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

A CAS500-1 (Compact Advanced Satellite) is a high-resolution Earth-observing satellite launched in Mar 2021 and being operated by National Land Satellite Center at NGII (National Geographic Information Institute). The mission of the satellite is the periodic monitoring of the land for efficient managements. Having completed the calibration and validation processes, CAS500-1 has been acquiring land images to generate the basic geospatial information that are topographicmaps, orthorectified images, and DEM (Digital Elevation Model). Using satellite data has a lot of advantages over aerial images in terms of repeatability, coverage, and accessibility. However, the spatial resolution is relatively lower than that of aerial images. This prohibits the large scale topographic mapping from the satellite data. Therefore, we conducted 1:5,000 large scale topographic mappings using CAS500-1 stereo data and assessed the accuracy. Two test areas were selected including accessible and inaccessible areas. Overlapping CAS500-1 data were automatically processed with GCP (Ground Control Points) chips for better positional accuracy. Then they are used for the epipolar resampled images that can be used for stereo-plotting. Through the stereo display quality assessment, we selected the optimal stereo set for each site. The accuracy of the resulted topographic maps was checked using ground truth data such as GNSS (Global Navigation Satellite System)-surveyed points over the accessible area and GCP chips in the inaccessible area, respectively. The experimental results showed the accuracy successfully met the requirement of 1:5,000 topographic map in Korea. We concluded that CAS500-1 data will have more potential for large scale mapping considering that CAS500-2 is scheduled to be launched in 2022 and cooperate with CAS500-1.

Conjugate Point Extraction for High-Resolution Stereo Satellite Images Orientation

오재홍,이창노 한국측량학회 2019 한국측량학회지 Vol.37 No.2

The stereo geometry establishment based on the precise sensor modeling is prerequisite for accurate stereo data processing. Ground control points are generally required for the accurate sensor modeling though it is not possible over the area where the accessibility is limited or reference data is not available. For the areas, the relative orientation should be carried out to improve the geometric consistency between the stereo data though it does not improve the absolute positional accuracy. The relative orientation requires conjugate points that are well distributed over the entire image region. Therefore the automatic conjugate point extraction is required because the manual operation is labor-intensive. In this study, we applied the method consisting of the key point extraction, the search space minimization based on the epipolar line, and the rigorous outlier detection based on the RPCs (Rational Polynomial Coefficients) bias compensation modeling. We tested different parameters of window sizes for Kompsat-2 across track stereo data and analyzed the RPCs precision after the bias compensation for the cases whether the epipolar line information is used or not. The experimental results showed that matching outliers were inevitable for the different matching parameterization but they were successfully detected and removed with the rigorous method for sub-pixel level of stereo RPCs precision.