• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.101-101
• /
• 2000

MSC(Multispectral Camera), which will be a unique payload on KOMPSAT-II, is designed to collect panchromatic and multi-spectral imagery with a ground sample distance of 1m and a swath width of 15km at 685km altitude in sun-synchronous orbit. The instrument is designed to have an orbit operation duty cycle of 20% over the mission life time of 3 years. MSC electronics consists of three main subsystems; PMU(Payload Management Unit), CEU(Camera Electronics Unit) and PDTS(Payload Data Transmission Subsystem). PMU performs all the interface between spacecraft and MSC, and manages all the other subsystems by sending commands to them and receiving telemetry from them with software protocol through RS-422 interface. CEU controls FPA(Focal Plane Assembly) which contains TDI(Timc Delay Integration) CCD(Charge Coupled Device) and its clock drivers. PMU provides a Master Clock to synchronize panchromatic and multispectral camera. PDTS performs compression, storage and encryption of image data and transmits them to the ground station through x-band.

• 한국수자원학회논문집
• /
• 제54권2호
• /
• pp.121-133
• /
• 2021

하천에서 발생하는 부유 물질은 주로 유역으로부터 유입되거나 하천 내에서 자생으로 발생하기도 하며, 퇴적되어 중장기적인 수질 오염을 초래할 수도 있는 중요한 수질 인자이다. 하지만, 부유물질의 재래식 계측방식은 점 단위 계측이기 때문에 노동 집약적이며 방대한 양의 자료를 취득하기는 어렵다. 따라서, 본 연구에서는 고해상도 다분광 위성영상을 제공하는 Sentinel-2 위성 자료를 이용하여 낙동강 전역에 대한 원격탐사 기반 부유 물질 농도 계측 기법을 개발하였다. 개발된 기법은 기존 원격탐사 기반 회귀식들의 한계점을 개선하고 낙동강 전체 영역의 지역적 특성을 반영하기 위해 기계학습 모형인 서포트 벡터 회귀(Support Vector Regression, SVR) 모형을 이용하여 다양한 파장대의 분광 밴드들과 밴드비(band ratios)를 고려하였으며, 이를 입력 변수들의 최적 조합으로 재귀적 특징 제거법(Recursive Feature Elimination, RFE)과 SVR의 각 변수별 가중계수를 활용하여 도출하였다. 가장 중요도가 높은 분광 밴드로는 Red-edge 파장대 영역에 속하는 705 nm 밴드가 산출되었으며, 최종적으로 구축된 SVR 모형을 선행 연구들에서 제시한 회귀식들과 비교한 결과, 가장 정확한 계측 결과를 제공하는 것으로 밝혀졌다. 본 연구에서 개발된 SVR 모형은 RFE를 통해 산출된 최적 분광 밴드 조합을 바탕으로 하기 때문에 기존 단일 분광 밴드 혹은 밴드비를 기반으로 구축된 회귀식들이 가지는 변수 의존도를 낮추는 동시에 더욱 정확한 부유물질 농도 공간분포를 제공할 수 있을 것으로 판단된다.

• 한국측량학회지
• /
• 제29권5호
• /
• pp.449-457
• /
• 2011

As automated image processing techniques have been required in multi-temporal/multi-sensor geospatial image applications, use of automated but highly invariant image matching technique has been a critical ingredient. Note that there is high possibility of geometric and spectral differences between multi-temporal/multi-sensor geospatial images due to differences in sensor, acquisition geometry, season, and weather, etc. Among many image matching techniques, the SIFT (Scale Invariant Feature Transform) is a popular method since it has been recognized to be very robust to diverse imaging conditions. Therefore, the SIFT has high potential for the geospatial image processing. This paper presents a performance test results of the SIFT on geospatial imagery by simulating various image differences such as shear, scale, rotation, intensity, noise, and spectral differences. Since a geospatial image application often requires a number of good matching points over the images, the number of matching points was analyzed with its matching positional accuracy. The test results show that the SIFT is highly invariant but could not overcome significant image differences. In addition, it guarantees no outlier-free matching such that it is highly recommended to use outlier removal techniques such as RANSAC (RANdom SAmple Consensus).

• 대기
• /
• 제14권2호
• /
• pp.11-22
• /
• 2004

A technique on atmospheric correction algorithm to the multi-band reflectance of Landsat TM imagery has been developed using an atmospheric radiation transfer model for eliminating the atmospheric and surface diffusion effects. Despite the fact that the technique of satellite image processing has been continually developed, there is still a difference between the radiance value registered by satellite borne detector and the true value registered at the ground surface. Such difference is caused by atmospheric attenuations of radiance energy transfer process which is mostly associated with the presence of aerosol particles in atmospheric suspension and surface irradiance characteristics. The atmospheric reflectance depend on atmospheric optical depth and aerosol concentration, and closely related to geographical and environmental surface characteristics. Therefore, when the effects of surface diffuse and aerosol reflectance are eliminated from the satellite image, it is actually corrected from atmospheric optical conditions. The objective of this study is to develop an algorithm for making atmospheric correction in satellite image. The study is processed with the correction function which is developed for eliminating the effects of atmospheric path scattering and surface adjacent pixel spectral reflectance within an atmospheric radiation model. The diffused radiance of adjacent pixel in the image obtained from accounting the average reflectance in the $7{\times}7$ neighbourhood pixels and using the land cover classification. The atmospheric correction functions are provided by a radiation transfer model of LOWTRAN 7 based on the actual atmospheric soundings over the Korean atmospheric complexity. The model produce the upward radiances of satellite spectral image for a given surface reflectance and aerosol optical thickness.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.351-353
• /
• 2003

We present a retrieval scheme for the remote sensing of evapotranspiration (ET) over rice paddy. To perform the retrieval, high-resolution airborne imagery of multi-spectral visible and thermal infrared data, and ground-based meteorological measurements are utilized. Our ET retrieval scheme is based on the basic principal of surface energy budget, which is a result of balance in longwave and shortwave radiation, latent heat, sensible heat, and energy flux into the ground. To partition the latent and sensible heat fluxes of interest from the energy balance equation, three basic parameters are of most concern, including albedo, surface temperature, and normalized difference vegetation index (NDVI). The NDVI and albedo can be easily derived from the visible and near infrared spectral data, while the surface tem-perature can be determined through the analysis of the infrared data with the Stefan Boltzmann law. From the airborne imagery taken on 28 April 2003, we observe very good dry and wet pixels that can be easily corre-sponded to the radiation and evaporation controlled crite-ria, respectively, and, hence, for the further use in defin-ing the evaporative fraction needed to partition sensible and latent heat fluxes from the net energy flux. The de-rived ET is compared with the in situ measurements.

• 대한원격탐사학회지
• /
• 제27권1호
• /
• pp.9-15
• /
• 2011

푸쉬브룸 스캐너 PAN영상과 MS영상 사이에는 오프셋이 존재하며 서로 다른 시간과 각도로 촬영하고 있다. 이로 인하여 구름과 같이 빠르게 움직이는 물체는 오정합 점들을 생성하며 이는 PAN영상과 MS영상간의 상호영상등록의 오차를 발생시킨다. 특히 구름(안개 및 스모그 포함)이 있는 기상조건 하에서 얻어진 위성영상은 구름에 의해 가려진 지형정보를 추출하는 데 있어 많은 문제를 야기하기 때문에 정확한 영상등록을 위해서는 효과적인 구름 탐지 및 제거 알고리즘이 필요하다. 구름 제거를 위한 관련 연구들은 크게 다음과 같은 세 가지로 나누어지는데 (1) 구름 검출 알고리즘을 통해 구름으로 여겨지는 영역을 분리하여 구름영역을 제거하는 방법 (2) 다중분광영상의 밴드정보를 이용하는 방법 (3) 다시기 영상정보를 이용하는 방법들로 나눌 수 있다. 본 연구에서는 구름 지역을 제거하는 방법과 다시기영상을 이용하는 방법을 사용하여 구름이 포함된 푸쉬브룸 스캐너 밴드간 영상등록의 정확도를 비교, 분석하였다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2004년도 학술발표회
• /
• pp.1271-1275
• /
• 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.

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

• 대한원격탐사학회지
• /
• 제22권6호
• /
• pp.553-563
• /
• 2006

본 연구의 목적은 MODIS 다중시기영상과 선형분광혼합화소분석(Linear Spectral Mixture Analysis : LSMA)을 이용하여 한반도의 토지피복도를 작성하는 것이다. 다양한 공간해상도와 광역적인 촬영스케일의 MODIS 영상에 LSMA를 이용하여 토지피복분류기 정확도의 향상과 한반도 생물계절적인 특성을 분석하고자 하였다. LSMA는 하나의 화소를 단일의 지표물로 가정하여 영상을 처리하는 기존의 기법과 달리 대상지의 토지피복 특성을 가장 잘 반영하는 순수한 물체의 화소값(Endmember)을 선택하여 자연환경요소들의 하나하나를 분리하는 기법이다. 본 연구에서 MODIS 다중시기 영상에 LSMA를 적용한 결과 남, 북한의 농경지 및 산림지역에 대한 서로 다른 생물계절적인 특성을 파악 할 수 있었으며, 이러한 결과 영상을 ISODATA 무감독분류기법을 통해서 대분류와 중분류하였다. 대분류에서는 79.94%의 전체 정확도를 보였으며, 농업지역은 85.45%, 산림지역은 88.12%로 다른 분류군들에 비해서 가장 높은 정확도를 보였다. 중분류에서는 산림지역과, 농업지역을 더욱 세분화하여 분류하였다. 전체정확도는 82.09%였으며, 활엽수림 86.96%, 논 85.38%로 분류군중 가장 높은 정확도를 나타냈다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.331-336
• /
• 1999

The optical sensors of Electro-Optical Camera (EOC) and Ocean Scanning Multi-spectral Imager (OSMI) aboard the Korea Multi-Purpose SATellite (KOMPSAT) will be placed in a sun synchronous orbit in 1999. The EOC and OSMI sensors are expected to produce the land mapping imagery of Korean territory and the ocean color imagery of world oceans, respectively. Utilization of the EOC and OSMI data would encompass the various fields of science and technology such as land mapping, land use and development, flood monitoring, biological oceanography, fishery, and environmental monitoring. Readiness of data support for user community is thus essential to the success of the KOMPSAT program. As part of testing such readiness prior to the KOMPSAT launch, we have performed the preliminary acceptance test for the KOMPSAT data processing system using the simulated EOC and OSMI data sets. The purpose of this paper is to demonstrate the readiness of the KOMPSAT data processing system, and to help data users understand how the KOMPSAT EOC and OSMI data are processed and archived. Test results demonstrate that all requirements described in the data processing specification have been met, and that the image integrity is maintained for all products. It is however noted that since the product accuracy is limited by the simulated sensor data, any quantitative assessment of image products can not be made until actual KOMPSAT images will be acquired.