• 대한원격탐사학회지
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• 제37권5_1호
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• pp.999-1011
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• 2021

다중 센서 영상으로부터 공간 및 시간해상도가 모두 높은 영상을 예측하는 시공간 융합에서 다중 센서 영상의 방사학적 불일치는 예측 성능에 영향을 미칠 수 있다. 이 연구에서는 다중 센서 위성영상의 서로 다른 분광학적 특성을 보정하는 방사보정이 융합 결과에 미치는 영향을 분석하였다. 두 농경지에서 얻어진 Sentinel-2, PlanetScope 및 RapidEye 영상을 이용한 사례연구를 통해 상대 방사보정의 효과를 정량적으로 분석하였다. 사례연구 결과, 상대 방사보정을 적용한 다중 센서 영상을 사용하였을 때 융합의 예측 정확도가 향상되었다. 특히 입력 자료 간 상관성이 낮은 경우에 상대 방사보정에 의한 예측 정확도 향상이 두드러졌다. 분광 특성의 차이를 보이는 다중 센서 자료를 서로 유사하게 변환함으로써 예측 성능이 향상된 것으로 보인다. 이 결과를 통해 상대 방사보정은 상관성이 낮은 다중 센서 위성영상의 시공간 융합에서 예측 능력을 향상시키기 위해 필요할 것으로 판단된다.

• 한국지구과학회지
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• 제32권6호
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• pp.560-574
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• 2011

주기적이고 지속적으로 자료를 얻을 수 있는 위성영상은 지표면의 변화를 모니터링 하기 위한 매우 효과적인 자료이다. 위성영상을 이용한 기존의 변화탐지 연구는 두 시점의 지표 특성을 각각 분석해 서로 비교하여 변화를 밝혀내는 연구를 주로 해왔다. 그러나 최근에는 연속성을 갖는 다중 시기 위성영상으로부터 전체적인 경향이나 단기적인 변화를 찾아내는 연구에 관심이 높아지고 있다. 이 연구에서는 다중 시기 위성영상을 분석하기 위해 3차원 웨이블릿 변환 기반의 기법을 제안하고 테스트해보았다. 3차원 웨이블릿 변환을 이용하면 자료의 중요한 특성은 보존하면서 차원을 줄이는 것이 가능하다. 또한 다중 시기의 자료로부터 주요 패턴을 간추려 내고 공간, 시간적으로 인접한 주변 화소와의 관계를 파악할 수 있다. 연구 결과, 3차원 웨이블릿 변환 기법은 전체적인 경향성이나 특별한 변화 특성을 빠른 시간내에 밝혀내는 데 유용할 뿐만 아니라 분해 방향에 따라 각기 다른 정보를 제공해 주는 하위 밴드를 통해 새로운 정보를 얻을 수 있을 것으로 기대된다.

• 한국측량학회지
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• 제35권3호
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• pp.125-132
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• 2017

IKONOS, QuickBird, Kompsat-2 등 서로 다른 고해상도 광학 센서로 취득된 다중시기 영상은, 취득 당시의 센서 자세나 환경의 차이에 의해 영상 등록(image registration)을 수행한 이후에도 여전히 지역적인 지형 불일치가 존재한다. 등록오차(registration noise)라고도 불리는 이러한 지형 불일치는 고해상도 다중시기 영상을 이용하여 공간정보를 추출하는 다양한 활용분야의 정확도를 떨어뜨리는 방해 요인으로 작용한다. 반대로, 등록오차를 추출하여 이를 효과적으로 제거한다면 결과적으로는 다중시기 고해상도 영상을 이용하여 추출되는 공간정보의 정확도를 높일 수 있다. 이에 본 연구에서는 지배적인 등록오차는 주로 영상 내 객체의 경계를 따라서 존재한다는 가정 하에, 경계강도 영상을 이용하여 등록오차를 추출한다. 추출된 등록오차의 지역적 분포특성을 고려하여 고해상도 영상 간 지형 불일치를 최소화하는 정밀 등록 기법을 제안한다. 제안 기법을 평가하기 위해, 고해상도 다중시기 광학위성 영상을 이용하여 실험지역을 구성한다. 등록오차 기반의 정밀 등록 기법 적용 결과와 수동으로 수행한 등록 결과와의 정량적/정성적 비교평가를 통해 제안 기법의 우수성을 판단하고자 한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.515-517
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• 2004

Although sustainable development of a city should in theory be based on updated spatial information like land cover/use changes, in practice there are no effective tools to get such information. However the development of satellite and sensor technologies has increased the supply of high resolution satellite data, allowing cost-effective, multi-temporal monitoring. Especially KOMPSAT-1(KOrea Multi-Purpose SATellite) acquired a large number of images of the whole Korean peninsula and covering some large cities a number of times. In this study land-use patterns and trends of Daejeon from the year 2000 to the year 2003 will be considered using land use maps which are generated by manual interpretation of multi-temporal KOMPSAT EOC imagery and to show the possibility of using high resolution satellite remote sensing data for urban analysis.

• 대한원격탐사학회지
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• 제18권1호
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• pp.13-23
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• 2002

A radiometric correction method is developed to apply multi-temporal KOMPSAT-1 EOC satellite images for the detection of land-cover changes b\ulcorner recognizing changes in reflection pattern. Radiometric correction was carried out to eliminate the atmospheric effects that could interfere with the image properly of the satellite data acquired at different multi-times. Four invariant features of water, sand, paved road, and roofs of building are selected and a linear regression relationship among the control set images is used as a correction scheme. It is found that the utilization of panchromatic multi-temporal imagery requires the radiometric scene standardization process to correct radiometric errors that include atmospheric effects and digital image processing errors. Land-cover with specific change pattern such as paddy field is extracted by seasonal change recognition process.

• 대한원격탐사학회지
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• 제31권4호
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• pp.321-330
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• 2015

Atmospheric correction is an essential part in time-series analysis on biophysical parameters of surface features. In this study, we tried to examine possible problems in atmospheric correction of multitemporal High Spatial Resolution (HSR) images obtained from two different sensor systems. Three KOMPSAT-2 and two IKONOS-2 multispectral images were used. Three atmospheric correction methods were applied to derive surface reflectance: (1) Radiative Transfer (RT) - based absolute atmospheric correction method, (2) the Dark Object Subtraction (DOS) method, and (3) the Cosine Of the Uun zeniTh angle (COST) method. Atmospheric correction results were evaluated by comparing spectral reflectance values extracted from invariant targets and vegetation cover types. In overall, multi-temporal reflectance from five images obtained from January to December did not show consistent pattern in invariant targets and did not follow a typical profile of vegetation growth in forests and rice field. The multi-temporal reflectance values were different by sensor type and atmospheric correction methods. The inconsistent atmospheric correction results from these multi-temporal HSR images may be explained by several factors including unstable radiometric calibration coefficients for each sensor and wide range of sun and sensor geometry with the off-nadir viewing HSR images.

• 대한원격탐사학회지
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• 제19권3호
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• pp.263-269
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• 2003

This research examined the capabilities of KOMPSAT-1 EOC images for the application of urban environment, including the urban changes of the study areas. This research is constructed in three stages: Firstly, for the application of change detection techniques, which utilizes multi-temporal remotely sensed data, the data normalization process is carried out. Secondly, the change detection method is applied for the systematic monitoring of land-use changes. Lastly, using the results of the previous stages, the land-use map is updated. Consequently, the patterns of land-use changes are monitored by the proposed scheme. In this research, using the multi-temporal KOMPSAT-1 EOC images and land-use maps, monitoring of urban growth was carried out with the application of land-use changes, and the potential and scope of the application of the EOC images were also examined.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.222-227
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• 2002

This research will examine into the capabilities of KOMPSAI-1 EOC image application in the field of urban environment and at the same time, with that as its foundation, come to understand the urban changes of the study areas. This research is constructed in three stages: Firstly, for application of change detection techniques, which utilizes multi-temporal remotely sensed data, the data normalization process is carried out. Secondly, change detection method is applied fur the systematic monitoring of land use changes, which utilizes multi-temporal EOC images. Lastly, by using the results of the application of land use changes, the existing land use map is updated. Consequently, the land-use change patterns are monitored, which utilize multi-temporal panchromatic EOC image data; and application potentials of ancillary data fur updating existing data can be presented. In this research, with the use of the land use change, monitoring of urban growth has been carried out, and the potential for the application of KOMPSAT-1 EOC images and the scope of application was examined. Henceforth, the future expansion of the scope of application of KOMPSAT-1 EOC image is anticipated.

• 대한원격탐사학회지
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• 제35권4호
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• pp.545-560
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• 2019

Unlike other critical forest diseases, pine pitch canker in Korea has shown rather mild symptoms of partial loss of crown foliage and leaf discoloration. This study used high-resolution satellite images to detect and monitor canopy decline by pine pitch canker. To enhance the subtle change of canopy reflectance in pitch canker damaged tree crowns, multi-temporal analysis was applied to two KOMPSAT multispectral images obtained in 2011 and 2015. To assure the spectral consistency between the two images, radiometric corrections of atmospheric and shadow effects were applied prior to multi-temporal analysis. The normalized difference vegetation index (NDVI) of each image and the NDVI difference (${\Delta}NDVI=NDVI_{2015}-NDVI_{2011}$) between two images were derived. All negative ΔNDVI values were initially considered any pine stands, including both pitch canker damaged trees and other trees, that showed the decrease of crown foliage from 2011 to 2015. Next, $NDVI_{2015}$ was used to exclude the canopy decline unrelated to the pitch canker damage. Field survey data were used to find the spectral characteristics of the damaged canopy and to evaluate the detection accuracy from further analysis.Although the detection accuracy as assessed by limited number of field survey on 21 sites was 71%, there were also many false alarms that were spectrally very similar to the damaged canopy. The false alarms were mostly found at the mixed stands of pine and young deciduous trees, which might invade these sites after the pine canopy had already opened by any crown damages. Using both ${\Delta}NDVI$ and $NDVI_{2015}$ could be an effective way to narrow down the potential area of the pitch canker damage in Korea.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.470-472
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• 2003

The primary goal in this paper is to analyze urban growth patterns using multi-temporal remote sensing images and geographic information data. In order to accomplish this purpose, firstly data pre-processing is carried out, and then land-use maps are generated with ancillary data source by heads-up on-screen digitizing. Lastly, using the results of the previous stages, the patterns of land-use and urban changes are monitored by the proposed scheme. In this research, using the multi-temporal images and geographic information data, monitoring of urban growth was carried out with the application of urban land-use changes.