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Research Article

Water body detection during drought and flood seasons using a Swin-Transformer with CAS500-1 satellite imagery

국토위성(CAS500-1) 영상을 활용한 Swin-Transformer 기반 갈수기홍수기 수체 탐지

Shinhyeon Choa
,
Wanyub Kimb
,
Doseob Ahnc
,
Seungchul Kimd
,
Sangil Kime
,
Yangwon Leef
,
Minha Choigh*
조 신현a
,
김 완엽b
,
안 도섭c
,
김 승철d
,
김 상일e
,
이 양원f
,
최 민하gh*
aPh.D Student, Department of Global Smart City, Sungkyunkwan University, Suwon, Korea
bPh.D Candidate, Department of Global Smart City, Sungkyunkwan University, Suwon, Korea
cPrincipal Researcher, Satellite Communication Infra Research Section, Electronics and Telecommunications Research Institute, Daejeon, Korea
dPrincipal Researcher, Satellite Communication Infra Research Section, Electronics and Telecommunications Research Institute, Daejeon, Korea
eSenior Engineer, Satellite Communication Infra Research Section, Electronics and Telecommunications Research Institute, Daejeon, Korea
fProfessor, Department of Spatial Information Engineering, Division of Earth Environmental System Science, Pukyong National University, Busan, Korea
gProfessor, Department of Water Resources, Sungkyunkwan University, Suwon, Korea
hProfessor, School of Civil, Architecture Engineering and Landscape Architecture, Sungkyunkwan University, Suwon, Korea
a성균관대학교 글로벌스마트시티융합전공 박사과정
b성균관대학교 글로벌스마트시티융합전공 박사수료
c한국전자통신연구원 위성통신인프라연구실 책임연구원
d한국전자통신연구원 위성통신인프라연구실 책임연구원
e한국전자통신연구원 위성통신인프라연구실 선임연구원
f부경대학교 지구환경시스템과학부 공간정보공학전공
g성균관대학교 수자원전문대학원 수자원학과 교수
h성균관대학교 건설환경공학부 교수
*Corresponding Author
31 January 2026. pp. 101-113
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Abstract

In recent years, the frequency of water-related disasters, such as droughts and floods, has increased. This phenomenon underscores the imperative for the development of methodologies for the monitoring of water bodies using high-resolution satellite data. High-resolution satellite imagery facilitates the precise monitoring of both large-scale water bodies and smaller reservoirs and river channels, offering substantial advantages for disaster response. These include the rapid identification of inundation areas during floods and the tracking of reservoir storage decline under drought conditions. The Compact Advanced Satellite 500-1 (CAS500-1), also referred to as the Korean National Satellite, offers 2-meter spatial resolution, facilitating more precise water body detection in comparison to conventional medium- and low-resolution satellite data. In this study, the Swin-Transformer model was applied to CAS500-1 imagery for quantitative assessment of the performance of water body detection. Additionally, the study investigated the applicability of the model under real hydrological conditions, utilizing case studies of drought and flood events. Preliminary findings based on confusion matrix indicators demonstrate that the Swin-Transformer model has a high degree of accuracy, with IoU values ranging from 0.94 to 0.97 and F1-scores ranging from 0.97 to 0.98, across a range of reservoir scales. Case studies revealed that low water levels and narrow tributary conditions in the Seomjin River and Imha Reservoir during drought affected Precision and Recall variations, while flood-season imagery of the Geum River (Gongju Weir) showed limited boundary detection due to cloud cover, water level rise, and turbid water. These findings demonstrate that combining CAS500-1 imagery with Transformer-based models enables robust water body detection. However, they also indicate the need for further enhancements under extreme hydrological events. This study corroborates the applicability of CAS500-1 data and is expected to contribute to the advancement of satellite-based monitoring systems for water resource management and disaster response to droughts and floods in Korea.

Keywords
Satellite remote sensing
Water body detection
Drought
Flood
CAS500-1

최근, 가뭄 및 홍수와 같은 수재해가 빈번하게 발생함에 따라, 이를 효율적으로 관리하기 위해 고해상도 위성 자료 기반의 수체 모니터링의 필요성이 증대되고 있다. 특히, 고해상도 위성 영상은 대규모 수계뿐만 아니라 소규모 저수지와 하천까지도 정밀하게 모니터링할 수 있어, 홍수 시 범람 지역의 신속한 파악이나 가뭄에 따른 저수량 감소 관측 등 재해 대응 측면에서도 큰 이점을 제공한다. 국토위성으로 불리는 차세대중형위성 1호(CAS500-1)는 2 m급 공간해상도를 제공하여 기존 중·저해상도 위성 자료보다 정밀한 수체 탐지가 가능하다. 본 연구에서는 CAS500-1 영상을 대상으로 Swin-Transformer 모델을 적용하여 수체 탐지 성능을 정량적으로 평가하고, 갈수기와 홍수기 사례를 통해 실제 수문학적 조건에서의 적용 가능성을 검토하였다. 혼동행렬 지표 기반 성능 분석 결과, Swin-Transformer는 다양한 규모의 저수지에서 IoU= 0.94-0.97, F1-score= 0.97-0.98을 기록하며 높은 정확도를 보였다. 사례 분석에서는 갈수기 섬진강과 임하호에서 수위 저하와 협소한 지류 조건이 Precision과 Recall 변동에 영향을 주었으며, 홍수기 금강 공주보에서는 구름 피복, 수위 상승, 탁수로 인해 경계부 탐지가 제한되는 현상이 나타났다. 이러한 결과는 CAS500-1 영상과 Transformer 기반 모델이 결합될 경우 안정적인 수체 탐지가 가능함을 보여주며, 동시에 극한 수문학적 상황에서는 추가적인 보완이 필요함을 드러낸다. 본 연구는 국토위성 자료의 활용 가능성을 확인하였으며, 향후 국내 수자원 관리와 가뭄·홍수 재해 대응을 위한 위성 기반 모니터링 체계 고도화에 기여할 수 있을 것으로 기대된다.

키워드
위성원격탐사
수체 탐지
갈수기
홍수기
국토위성 1호
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Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 59
  • No :1
  • Pages :101-113
  • Received Date : 2025-10-13
  • Revised Date : 2025-12-15
  • Accepted Date : 2025-12-16
  • DOI :https://doi.org/10.3741/JKWRA.2026.59.1.101
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