• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1553-1563
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• 2023

The Geostationary Ocean Color Imager-II (GOCI-II) is a satellite designed for ocean color observation, covering the Northeast Asian region and the entire disk of the Earth. It commenced operations in 2020, succeeding its predecessor, GOCI, which had been active for the previous decade. In this study, we aimed to enhance the atmospheric correction algorithm, a critical step in producing satellite-based ocean color data, by performing cross-calibration on the GOCI-II near-infrared (NIR) band using the GOCI NIR band. To achieve this, we conducted a cross-calibration study on the top-of-atmosphere (TOA) radiance of the NIR band and derived a vicarious calibration gain for two NIR bands (745 and 865 nm). As a result of applying this gain, the offset of two sensors decreased and the ratio approached 1. It shows that consistency of two sensors was improved. Also, the Rayleigh-corrected reflectance at 745 nm and 865 nm increased by 5.62% and 9.52%, respectively. This alteration had implications for the ratio of Rayleigh-corrected reflectance at these wavelengths, potentially impacting the atmospheric correction results across all spectral bands, particularly during the aerosol reflectance correction process within the atmospheric correction algorithm. Due to the limited overlapping operational period of GOCI and GOCI-II satellites, we only used data from March 2021. Nevertheless, we anticipate further enhancements through ongoing cross-calibration research with other satellites in the future. Additionally, it is essential to apply the vicarious calibration gain derived for the NIR band in this study to perform vicarious calibration for the visible channels and assess its impact on the accuracy of the ocean color products.

• 프린팅코리아
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• v.9 no.12
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• pp.108-111
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• 2010

한국인쇄학회(회장 구철회) 정기총회 및 추계학술논문발표회가 지난 11월 19일 오후 1시부터 서울인쇄정보센터 7층 강당에서 열렸다. 논문발표회에는 백용국 조선일보 차장의 'Gray balance를 활용한 신문인쇄 품질 향상을 위한 연구', 박정민 광명잉크 수석연구원의 'Vegetable Oil Ester에 따른 Offset 잉크의 물성 변화에 관한 연구', 이원규 부경대학교 대학원생의 '국내 오프셋 인쇄물 평가를 위한 최적의 Proofing 조건에 관한 연구', 오승재 부경대학교 대학원생의 '일반 교정인쇄물과 국내 오프셋 인쇄물의 비교 평가에 관한 연구', 송스엽 광명잉크 대리의 '로진변성페놀수지의 Cooking 온도에 따른 Varnish Rheology 물성 변화에 관한 연구', 허경영 (주)젠켐 대리의 '무극성 플라스틱 소재용 잉크 개발 및 소재의 부차성에 관한 연구', 권희경 부경대학교 대학원생의 '폐잉크를 이용한 스크린 인쇄용 블랙 잉크 제조에 관한 연구', 문성환 국군인쇄창 7급의 '국내인쇄환경에서 친환경잉크를 이용한 오프셋 인쇄의 색재현에 관한 연구' 등의 발표됐다. 본지에서는 '국내 오프셋 인쇄물 평가를 위한 최적의 Proofing 조건에 관한 연구'를 소개한다.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1259-1268
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• 2021

The 2nd Geostationary Ocean Color Imager (GOCI-II) is the successor to the Geostationary Ocean Color Imager (GOCI), which employs one near-ultraviolet wavelength (380 nm) and eight visible wavelengths(412, 443, 490, 510, 555, 620, 660, 680 nm) and three near-infrared wavelengths(709, 745, 865 nm) to observe the marine environment in Northeast Asia, including the Korean Peninsula. However, the multispectral radiance image observed at satellite altitude includes both the water-leaving radiance and the atmospheric path radiance. Therefore, the atmospheric correction process to estimate the water-leaving radiance without the path radiance is essential for analyzing the ocean environment. This manuscript describes the GOCI-II standard atmospheric correction algorithm and its initial phase validation. The GOCI-II atmospheric correction method is theoretically based on the previous GOCI atmospheric correction, then partially improved for turbid water with the GOCI-II's two additional bands, i.e., 620 and 709 nm. The match-up showed an acceptable result, with the mean absolute percentage errors are fall within 5% in blue bands. It is supposed that part of the deviation over case-II waters arose from a lack of near-infrared vicarious calibration. We expect the GOCI-II atmospheric correction algorithm to be improved and updated regularly to the GOCI-II data processing system through continuous calibration and validation activities.