• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.128-133
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• 1998

To assess the flood damages and to provide necessary information for preventing future catastrophe, it is necessary to appraise the inundated area with more accurate and rapid manner. This study attempts to evaluate the potential of satellite synthetic aperture radar (SAR) data for mapping of flood inundated area in southern part of Korea. JERS L-band SAR data obtained during the summer of 1997 were used to delineate the inundated areas. In addition, Landsat TM data were also used for analyzing the land cover condition before the flooding. Once the two data sets were co-registered, each data was separately classified. The water surface areas extracted from the SAR data and the land cover map generated using the TM data were overlaid to determine the flood inundated areas. Although manual interpretation of water surfaces from the SAR image seems rather simple, the computer classification of water body requires clear understanding of radar backscattering behavior on the earth's surfaces. It was found that some surface features, such as rice fields, runaway, and tidal flat, have very similar radar backscatter to water surface. Even though satellite SAR data have a great advantage over optical remote sensor data for obtaining imagery on time and would provide valuable information to analyze flood, it should be cautious to separate the exact areas of flood inundation from the similar features.

• 대한공간정보학회지
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• 제12권2호
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• pp.67-71
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• 2004

위성영상의 종류가 증가하고 취득이 용이해 짐에 따라 위성영상을 이용한 수치고도모형의 생성에 관한 연구가 활발히 진행되어 왔다. SPOT의 경우 $60km{\times}60km$에 해당하는 광범위한 지역에 대한 영상을 취득할 수 있어 넓은 지역에 대한 수치고도모형을 생성 할 수 있는 이점이 있다. 기존의 엄밀센서모형(Rigorous Sensor Model)의 경우 위성의 천문력자료(Ephemeris Data)와 지상기준점을 사용하여 복잡한 과정을 거쳐 DEM을 생성하였으나 본 연구에서는 직접선형변환(DLT)에 기반을 둔 대안적 모형화 기법을 이용하여 DEM을 생성해 보았다. 결과적으로 직접선형 변환의 경우 소수의 기준점을 통하여 양호한 품질의 DEM을 취득할 수 있음을 확인 할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.197-201
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• 2002

The high prices of satellite images prevent researchers from studying remote sensing and most non-professional people doesn't have the simple and easy solutions for the manipulation of satellite images. "Integrated Management of Satellite Imagery Information" project which will be promoted by ETRI (Electronics and Telecommunications Research Institute) will provide the solutions for the above mentioned problems. We will introduce the archiving center in this study. This includes the data construction, storage, management and distribution. We first review the background for this archiving center and introduce the interior and foreign institutes which archive and distribute satellite images. We review our H/W system and S/W system briefly. Finally, the further service of our project will be suggested. Since we will distribute the satellite images (Landsat, SPOT, JERS, Corona, Kompast-1) and will receive Landsat7 ETM+ in 2003 you, this will help the professional work dealing with the satellite image and attract the non-professional people for simple and easy manipulation solutions of satellite image.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.261-265
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• 2004

The purpose of this study is to present a standardized scheme for providing agriculture-related information at various spatial resolutions of satellite images including Landsat＋ETM, KOMPSAT-1 EOC, ASTER VNIR, and IKONOS panchromatic and multi-spectral images. The satellite images were interpreted especially for identifying agricultural areas, crop types, agricultural facilities and structures. The results were compared with the land cover/land use classification system suggested by Ministry of Construction & Transportation based on NGIS (National Geographic Information System) and Ministry of Environment based on satellite remote sensing data. As a result, high-resolution agricultural land cover map from IKONOS imageries was made out. The results by IKONOS image will be provided to KOMPSAT-2 project for agricultural application.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.684-687
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• 2006

Airborne imagery must be precisely orthorectified to be used as geographical information data. GPS/INS (Global Positioning System/Inertial Navigation System) and LIDAR (LIght Detection And Ranging) data were employed to automatically orthorectify airborne images. In this study, 154 frame airborne images and LIDAR vector data were acquired. LIDAR vector data were converted to raster image for employing as reference data. To derive images with constant brightness, flat field correction was applied to the whole 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 using 50 ground control points collected in arbitrary selected five images and LIDAR intensity image. In validation results, RMSE (Root Mean Square Error) was 0.365 smaller then two times of pixel spatial resolution at the surface. It is possible that the derived mosaicked airborne image by this automatic orthorectification method is employed as geographical information data.

• 대한원격탐사학회지
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• 제11권3호
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• pp.101-116
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• 1995

최근 안전성과 경제성을 고려한 교통자료획득 방법으로 인공위성 영상자료를 사용하는 기술이 논의되어졌다. 본 논문은 인공위성영상을 이용한 고속도로 교통량 측정 자동화에 관한 연 구로서, 현재 사용되고 있는 교통량 측정방법의 단점 및 문제점을 평가, 분석하였으며, 본 보고서 에서 제안된 인공위성영상을 이용한 방안의 적용 및 가능성을 연구, 분석 하였다. 기존 인공위성 영상자료의 해상도가 교통자료획득에 적합하지 않으므로, 사진영상에 제안된 방 안을 도입하여, 실효성에 바탕을 둔 적용 여부를 검증하였다. 차량종류 및 교통량 측정에 필요한 인공위성영상의 해상도를 구하기 위하여 세 단계 (1m, 2m, 3,)의 사진영상해상도가 검토되었으며, 본 연구에서 제안된 일련의 영상처리 결과를 분석하였다. 전색성(panchromatic) 영상에서 도로와 차량의 반사율이 유사함으로, 도로상에서 차량을 탐지하 기 위하여 차량의 반사율을 이용하지않고 차량그림자의 반사율을 이용하였으며, 두가지 처리방법 이 제시되었다. 또한 차량종류를 구분하기위하여 여러가지 형태계수를 개발, 적용하였으며, 처리 과정을 상세히 설명하였다.

• 환경정책연구
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• 제8권2호
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• pp.1-23
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• 2009

본 연구는 레이더 위성영상을 활용한 침수피해 지역 파악 및 그 완화방안의 도출을 위해 실제 침수지역을 대상으로 레이더 위성 영상의 침수피해에의 활용가능성을 살펴보았다. 이를 위하여 시계열 레이더 위성영상 자료를 활용하여 홍수에 취약한 침수 지역을 추출하고, 동일지역의 토지이용도에 대한 GIS 중첩분석을 통하여 토지이용 현황별 침수피해를 분석하였다. 사례 분석지역의 경우 침수피해가 심한 토지이용 형태는 농경지와 숲으로 나타났다. 본 연구는 레이더 위성영상을 활용하여 구축 가능한 침수피해 지도를 바탕으로 침수피해 완화를 위한 대응정책도 함께 논의하였다. 침수가 발생할 경우 긴급복구와 같은 위기대응적 접근도 중요하지만 무엇보다도 침수피해 지도와 같은 자료를 기반으로 위험한 지역에 건물의 입지를 제한하는 등 상습 침수피해 지역이 개발되지 않도록 예방적 차원에서의 토지 이용적 접근을 하여야 할 것이다. 본 연구에서 제안한 방안은 레이더 위성 영상의 환경 분야 활용과 침수피해를 최소화하는 방안의 일부이며, 레이더 위성영상은 대규모 홍수와 같은 재해문제 이외에도 다양한 환경 분야에 있어 활용 잠재력이 높으므로 향후 다양한 지역을 대상으로 레이더 위성영상을 여러 환경문제에 적용하는 연구가 계속되어야 할 것이다.

• 대한원격탐사학회지
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• 제28권6호
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• pp.683-691
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• 2012

High resolution satellite images are now widely used for a variety of mapping applications including photogrammetry, GIS data acquisition and visualization. As the spectral and spatial data size of satellite images increases, a greater processing power is needed to process the images. The solution of these problems is parallel systems. Parallel processing techniques have been developed for improving the performance of image processing along with the development of the computational power. However, conventional CPU-based parallel computing is often not good enough for the demand for computational speed to process the images. The GPU is a good candidate to achieve this goal. Recently GPUs are used in the field of highly complex processing including many loop operations such as mathematical transforms, ray tracing. In this study we proposed a technique for parallel processing of high resolution satellite images using GPU. We implemented a spectral radiometric processing algorithm on Landsat-7 ETM+ imagery using CUDA, a parallel computing architecture developed by NVIDIA for GPU. Also performance of the algorithm on GPU and CPU is compared.

• Korean Journal of Geomatics
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• 제3권1호
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• pp.33-41
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• 2003

Every year, several typhoons hit the Korean peninsula and cause severe damage. For the prevention and accurate estimation of these damages, real time or almost real time flood information is essential. Because of weather conditions, images taken by optic sensors or LIDAR are sometimes not appropriate for an accurate estimation of water areas during typhoon. In this case SAR (Synthetic Aperture Radar) images which are independent of weather condition can be useful for the estimation of flood areas. To get detailed information about floods from satellite imagery, accurate classification of water areas is the most important step. A commonly- and widely-used classification methods is the ML(Maximum Likelihood) method which assumes that the distribution of brightness values of the images follows a Gaussian distribution. The distribution of brightness values of the SAR image, however, usually does not follow a Gaussian distribution. For this reason, in this study the ANN (Artificial Neural Networks) method independent of the statistical characteristics of images is applied to the SAR imagery. RADARS A TSAR images are primarily used for extraction of water areas, and DEM (Digital Elevation Model) is used as supplementary data to evaluate the ground undulation effect. Water areas are also extracted from KOMPSAT image achieved by optic sensors for comparison purpose. Both ANN and ML methods are applied to flat and mountainous areas to extract water areas. The estimated areas from satellite imagery are compared with those of manually extracted results. As a result, the ANN classifier performs better than the ML method when only the SAR image was used as input data, except for mountainous areas. When DEM was used as supplementary data for classification of SAR images, there was a 5.64% accuracy improvement for mountainous area, and a similar result of 0.24% accuracy improvement for flat areas using artificial neural networks.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.283-285
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• 2003

This paper describes a data fusion method for high spatial resolution satellite imagery. The pixels located around an object edge have spectral mixing because of the geometric primitive of pixel. The larger a size of pixel is, the wider an area of spectral mixing is. The intensity of pixels adjacent edges were modified by the spectral characteristics of the pixels located inside of objects. The methods developed in this study were tested using IKONOS Multispectral and Pan data of a part of Jeju-shi in Korea. The test application shows that the spectral information of the pixels adjacent edges were improved well.