• 대한토목학회논문집
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• 제32권1D호
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• pp.89-94
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• 2012

범용센서모델의 한 종류인 비례다항식 모델(RFM: Rational Function Model)은 광학영상의 센서모델링분야에서 활발히 활용되고 있으나 SAR영상에 대한 적용은 미진한 실정이다. 본 연구에서는 스테레오 TerraSAR-X영상을 대상으로 RF 모델링을 적용하여 적용방법의 타당성과 효율성에 대해 분석하였다. 또한 본 연구성과의 DSM(Digital Surface Model)과 기존 상용 소프트웨어에서 생성된 DSM을 다양한 측면에서 비교 분석하였다. 그 결과 RF 모델링 기법이 SAR영상의 적용 시에도 매우 효과적이며 실용적으로 적용 가능함을 알 수 있었다.

• 한국측량학회지
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• 제32권6호
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• pp.607-615
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• 2014

RVI (Radar Vegetation Index) has shown some promise in the vegetation fields, but its relationship with MVI (Multispectral Vegetation Index) is not known in the context of various land covers. Presented herein is a comparative analysis of the MVI values derived from the LANDSAT-8 and RVI values originating from the RADARSAT-2 quad-polarimetric SAR (Synthetic Aperture Radar) data. Among the various multispectral vegetation indices, NDVI (Normalized Difference Vegetation Index) and SAVI (Soil Adjusted Vegetation Index) were used for comparison with RVI. Four land covers (urban, forest, water, and paddy field) were compared, and the patterns were investigated. The experiment results demonstrated that the RVI patterns of the four land covers are very similar to those of NDVI and SAVI. Thus, during bad weather conditions and at night, the RVI data could serve as an alternative to the MVI data in various application fields.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.31.4-32
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• 2008

The microwave instruments are used many areas of the space remote sensing and space science applications. The imaging radar of synthetic aperture radar (SAR) is well known microwave radar sensor for earth surface and ocean research. Unlike radar, microwave radiometer is passive instrument and it measures the emission energy of target, i.e. brightness temperature BT, from earth surface and atmosphere. From measured BT, the geophysical data like cloud liquid water, water vapor, sea surface temperature, surface permittivity can be retrieved. In this paper, the radiometer characteristics, system configuration and principle of BT measurement are described. Also the radiometer instruments TRMM, GPM, SMOS for earth climate, and ocean salinity research are introduce. As first korean microwave payload on STSAT-2, the DREAM (Dual-channels Radiometer for Earth and Atmosphere Monitoring) is described the mission, system configuration and operation plan for life time of two years. The main issues of DREAM unlike other spaceborne radiometers, will be addressed. The calibration is the one of main issues of DREAM mission and how it contribute on the space borne radiometer. In conclusion, the radiometer instrument to space science application will be considered.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.547-550
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• 2001

Through matched filtering synthetic aperture radar (SAR) produces high-resolution imagery from data collected by a relative small antenna. While the impulse response obtained by the matched filter approach produces the best achievable signal-to-noise ratio, large sidelobes must be reduced to obtain higher-resolution SAR images. So, many enhancement methods of SAR imagery have been proposed. As a deconvolution method, the phase-extension inverse filtering is based on the characteristics of the matched filtering used in SAR imaging. It improves spatial resolution as well as effectively suppresses the sidelobes with low computational complexity. In the phase-extension inverse filtering, the impulse response is obtained from simulation with a point target. But in a real SAR environment, for example ERS-1, the impulse response is distorted by many non-ideal factors. So, in the phase-extension inverse filtering for a real SAR processing, the magnitudes of the frequency transfer function have to be compensated to produce more desirable results. In this paper, an estimation method to obtain a more accurate impulse response from a real SAR image is studied. And a compensation scheme to produce better performance of the phase-extension inverse filtering is also introduced.

• 한국항공우주학회지
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• 제43권5호
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• pp.466-471
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• 2015

본 논문에서는 광역 관측을 위하여 새롭게 제안되고 있는 TOPS SAR 운용기법에 대한 모드 설계 및 성능 분석을 수행하였다. TOPS 모드는 기존 ScanSAR 모드의 단점인 scalloping을 개선하기 위하여 새롭게 제안된 모드로서, SAR 진행방향으로 안테나 빔을 조향하면서 영상 데이터를 획득하는 새로운 SAR 영상 획득 기술이다. 본 논문에서는 TOPS 모드에 대한 기술적 운용 개념을 소개하고, SAR 운용 변수를 추출하기 위한 모드 설계 결과를 제시한다. 또한 설계된 모드 변수를 이용하여 SAR 주요 성능인 IRF, NESZ, 및 DTAR을 분석하여 제시한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.111-114
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• 2004

Object-based segmentation is the first essential step for image processing applications. Recently, SAR (Synthetic Aperture Radar) segmentation techniques have been developed, however not enough to preserve the significant information contained in the small regions of the images. The proposed method is to partition an SAR image into homogeneous regions by using a fuzzy hit-or-miss operator with an inherent spatial transformation, which endows to preserve the small regions. In our algorithm, an iterative segmentation technique is formulated as a consequential process. Then, each time in iterating, hypothesis testing is used to evaluate the quality of the segmented regions with a homogeneity index. The segmentation algorithm is unsupervised and employed few parameters, most of which can be calculated from the input data. This comparative study indicates that the new iterative segmentation algorithm provides acceptable results as seen in the tested examples of satellite images.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.165-166
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• 2008

Bistatic spotlight synthetic aperture radar(BSSAR) with single track configuration uses the transmitter and the receiver which travel along the single track such as the leader-follower. For the BSSAR imaging, we modify the range migration algorithm. In time domain, we make the monostatic SAR using shifting of path, Then, in frequency domain, we compensate the separated distance between the scene center and the flight path using the principle of the stationary phase (PSP).

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.195-198
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• 2000

Microstrip antenna for SAR applications is designed with microwave composite laminates and Nomex honeycomb cores, which becomes an aircraft's structural panel. This study demonstrated fabrication, design procedures and structural and electrical performances of complex antenna system presented. For validating structural rigidity, 3-point bending test is performed, and simulation results for the complex antenna array are compared with measurements for its electrical performance. The results show that this antenna system can be applied in dual polarized synthetic aperture radar and has a good flexural stiffness with comparison of previous sandwich constructions.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 춘계학술발표회
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• pp.35-41
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• 2007

인공위성영상을 이용한 해양정보 추출을 위하여 SAR 위성영상을 이용한 해수유통 정보 추출을 연구하였다. SAR(Synthetic Aperture Radar) 위성영상의 도플러 쉬프트 정보를 이용한 해수유동 정보 추출은 적용기술의 근본적 한계로 인하여 실제 유속이 아니라 위성궤도의 법선방향에 대한 유속강도만을 제시하는 문제가 있다. 이러한 한계 및 문제점을 극복하기 위하여 본 연구에서는 위성영상 촬영과 통일한 시간에 동일한 해역에서 해수유통을 관측하고, 관측된 해수유통 정보를 이용하여 위성영상에서 추출된 해수유동 정보를 보완 검증 하였다. 위성영상 추출 해수유통정보의 위성궤도 법선방향 유속강도는 관측된 해수유통 유향분포도에 근거하여 실제 해수유동 유향에 맞게 보정될 수 있었으며, 보정된 해수유통 정보는 실제 해수유동 분포를 잘 반영할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.360-362
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• 2003

This paper presents simple feature-based approaches for full- and/or semi-automatic extraction, selection, and localization (center-determination) of ground control points (GCPs) for radargrammetry using airborne synthetic aperture radar (SAR) images. Test results using airborne NASA/JPL TOPSAR images in Taiwan verify that the registration accuracy is about 0.8${\sim}$1.4 pixels. In c.a. 30 minutes, 1500${\sim}$3000 GCPs are extracted and their point centers in a SAR image of about 512 ${\times}$ 512 pixels are determined on a personal computer.