• Title/Summary/Keyword: Landsat-8

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Analysis on optical property in the South Sea of Korea by using Satellite Image : Study of Case on red tide occurrence in August 2013 (위성영상을 활용한 한국 남해의 광학적 특성 연구 : 2013년 8월 발생한 적조 사례를 중심으로)

  • Bak, Su-Ho;Yoon, Hong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.11 no.7
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    • pp.723-728
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    • 2016
  • This study is analyzed the optical property of red tide pixel by using Landsat-7 ETM+, Landsat-8 OLI and COMS/GOCI image. In order to sample red tide pixel, Landsat-7, 8 true color image were used and obtained coordinate of red tide pixel in the true color image. Normalized water leaving radiance(nLw) and absorption coefficient were obtained from GOCI image in the same coordinate of the true color image. When red tide was not occurred the main absorption range was 412nm and 660nm but when red tide occurred it was 660nm and absorption coefficient in 412nm are drastically reduced. It made no difference of nLw spectrum between red tide pixel and non red tide pixel in nLw, but the absolute value of nLw was low than non red tide pixel, especially 660nm and 680nm wavelength sharply decrease.

Absolute Radiometric Calibration for KOMPSAT-3 AEISS and Cross Calibration Using Landsat-8 OLI

  • Ahn, Hoyong;Shin, Dongyoon;Lee, Sungu;Choi, Chuluong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.4
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    • pp.291-302
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    • 2017
  • Radiometric calibration is a prerequisite to quantitative remote sensing, and its accuracy has a direct impact on the reliability and accuracy of the quantitative application of remotely sensed data. This paper presents absolute radiometric calibration of the KOMPSAT-3 (KOrea Multi Purpose SATellite-3) and cross calibration using the Landsat-8 OLI (Operational Land Imager). Absolute radiometric calibration was performed using a reflectance-based method. Correlations between TOA (Top Of Atmosphere) radiances and the spectral band responses of the KOMPSAT-3 sensors in Goheung, South Korea, were significant for multispectral bands. A cross calibration method based on the Landsat-8 OLI was also used to assess the two sensors using near simultaneous image pairs over the Libya-4 PICS (Pseudo Invariant Calibration Sites). The spectral profile of the target was obtained from EO-1 (Earth Observing-1) Hyperion data over the Libya-4 PICS to derive the SBAF (Spectral Band Adjustment Factor). The results revealed that the TOA radiance of the KOMPSAT-3 agree with Landsat-8 within 5.14% for all bands after applying the SBAF. The radiometric coefficient presented here appears to be a good standard for maintaining the optical quality of the KOMPSAT-3.

Validation of the Radiometric Characteristics of Landsat 8 (LDCM) OLI Sensor using Band Aggregation Technique of EO-1 Hyperion Hyperspectral Imagery (EO-1 Hyperion 초분광 영상의 밴드 접합 기법을 이용한 Landsat 8 (LDCM) OLI 센서의 방사 특성 검증)

  • Chi, Junhwa
    • Korean Journal of Remote Sensing
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    • v.29 no.4
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    • pp.399-406
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    • 2013
  • The quality of satellite imagery should be improved and stabilized to satisfy numerous users. The radiometric characteristics of an optical sensor can be a measure of data quality. In this study, a band aggregation technique and spectral response function of hyperspectral images are used to simulate multispectral images. EO-1 Hyperion and Landsat-8 OLI images acquired with about 30 minutes difference in overpass time were exploited to evaluate radiometric coefficients of OLI. Radiance values of the OLI and the simulated OLI were compared over three subsets covered by different land types. As a result, the index of agreement shows over 0.99 for all VNIR bands although there are errors caused by space/time and sensors.

Assessment of the Relationship between Air Temperature and TOA Brightness Temperature in Different Seasons Using Landsat-8 TIRS (Landsat-8 위성의 열적외 센서를 활용한 대기온도와 밝기온도의 계절별 상관관계 분석)

  • CHOUNG, Yun-Jae;CHUNG, Youn-In;CHOI, Soo-Young
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.2
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    • pp.68-79
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    • 2018
  • In general, Top Of Atmosphere(TOA) brightness temperature is closely related to air temperature. Brightness temperature can be derived from the Thermal Infra-Red Sensors (TIRS) of the earth observation satellites such as the Landsat series. The TIRS instrument of the Landsat-8 satellite collects the two spectral bands (Bands 10 and 11) that measure brightness temperature. In this research, the relationship between the air temperature data measured by the weather stations in Seoul, South Korea and the brightness temperature data separately derived from Bands 10 and 11 of the Landsat-8 satellite were assessed in the different seasons through the correlation analysis. The statistical results led to the following conclusions. First, brightness temperature is closely related to air temperature in order of Spring, Autumn, Winter and Summer. Second, when air temperature increases, brightness temperature also increases in Spring, Autumn and Winter but decreases in Summer. Third, Band 10 has a closer relationship to air temperature than Band 11.

Analysis of a Spatial Distribution and Nutritional Status of Chlorophyll-a Concentration in the Jinyang Lake Using Landsat 8 Satellite Image (Landsat 8호 영상을 이용한 진양호의 클로로필 a 농도의 공간분포와 영양상태 분석)

  • Jang, Min Won;Cho, Hyun Kyung;Kim, Sang Min
    • Journal of Korean Society on Water Environment
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    • v.35 no.1
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    • pp.1-8
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    • 2019
  • The purpose of this study is to evaluate the nutritional status of Lake Jinyang using Landsat 8 satellite image band correlated with chlorophyll-a, which is also related to algae proliferation. We selected 20 Landsat 8 images dating from 2013 to 2017, taken close to water quality measurement date when the cloud cover was less than 20 %. Based on the results of the previous studies, analyzing the correlation between chlorophyll-a, and Landsat 8 satellite image band, we selected near infrared wavelength, band 5 which is closely related to the population of algae. The nutritional status was classified using the Aizaki trophic state index (TSIm). The results of the regression equation between band 5 and the observed chlorophyll-a data was used to calculate chlorophyll-a for the image data from 2013 to 2017. The concentration of chlorophyll-a ranged from 3 to $16.1mg/m^3$. To illustrate the spatial distribution of chlorophyll-a within the lake, the chlorophyll-a concentration was divided into five grades. The images on October 14, 2014 and April 10, 2016 showed relatively high value of chlorophyll-a, while January 18, 2015 and December 6, 2016 chlorophyll-a value were below 5. The images on October 14, 2014 and April 10, 2016 were rated as eutrophic status in most areas. The results of simulating water quality for the day when the water quality was not measured resulted to an approximate value for the Panmun station while the Naedong station needed some corrections.

Spatial Analysis of Garorim bay by using Tidal Flat Surface Temperature and NDVI (가로림만의 갯벌 지표온도와 식생지수에 의한 공간분석)

  • Jeong, Jong-Chul
    • Journal of Cadastre & Land InformatiX
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    • v.47 no.1
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    • pp.27-35
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    • 2017
  • Human activity such as agriculture, industrial development and urban sprawl has been the major threat to wetlands ecosystem, which have caused the greatest losses of coastal wetlands. The Garorim bay provides one of the most important wetland habitate and Ministry of Oceans and Fisheries designated Garorim bay to marine ecosystem protected area in July 2016. The purpose of this research is to analysis the spatial pattern of Garorim bay using Landsat 5 (TM), Landsat 7 (ETM+), Landsat 8 (OLI & TIRS). The surface temperature and NDVI of Garorim bay were processed with spatial analysis method and time series analysis were applied to 25 years Landsat satellite 19 images. The results of time series distribution map compared with the several wetland habitate on remotely sensed images. Landsat images showed the change area of wetland vegetation distribution from 1988 to 2014. The southern part habitate of Garorim bay have been changed with vegetation patterns on coastal wetland which were covered with tidal flat.

Comparison of Normalization Difference Vegetation Index due to difference in Landsat satellite sensor (Landsat 위성의 센서 차이에 의한 정규식생분포지수 비교)

  • Kwak, Jaehwan;Bhang, Kon Joon;Lee, Jin-Duk
    • Proceedings of the Korea Contents Association Conference
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    • 2014.11a
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    • pp.135-136
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    • 2014
  • 지구온난화에 따른 이상기후현상을 해결하기 위해 인공위성영상을 이용한 식생의 변화유무와 특성파악이 중요하다. 특히, 인공위성의 근적외선 영역과 가시광선 영역을 이용한 정규식생분포지수는 식생의 활력도를 파악하고 변화유무를 판단하는 지표로서 많이 사용되고 있다. 하지만, 최근 발사된 Landsat 8 OLI의 경우 정규식생분포지수에 영향을 주는 근적외선 밴드의 파장대역이 기존의 TM/ETM+ 위성의 근적외선 밴드의 파장대역보다 감소하였다. 또한 이러한 파장대역 변화에 의한 정규식생분포지수의 차이에 대해서 공식적으로 연구한 사례가 없다. 그러므로 본 연구는 Landsat 8 OLI 위성영상과 Landsat 7 ETM+ 위성영상을 식생이 활발한 여름철(9월)과 그렇지 않은 겨울철(1월)의 영상을 각각 취득하여, 식생, 도심지, 도로, 농경지, 나지의 5가지 항목으로 분류하여 각각의 정규식생분포지수를 비교해보고 상관관계분석을 시도하였다.

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Fully Automated Generation of Cloud-free Imagery Using Landsat-8 (Landsat-8을 이용한 자동화된 구름 제거 영상 생성)

  • Kim, Byeong Hee;Kim, Yong;Han, You Kyung;Choi, Won Seok;Kim, Yong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.2
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    • pp.133-142
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    • 2014
  • Landsat is one of the popular satellites for observing land surface that is used in various areas including monitoring, detecting and classifying changes in land surface. However, shades, which cloud itself and its shadow, interrupted often clear observation and analysis of ground surface. For this reason, the process of removing shades and restoring original ground surfaces are critical for geospatial users. This study is planned to recommend a methodology for more accurate and clear images of Landsat-8 sensor, which provided two additional bands of costal/aerosol and cirrus. In fact, those bands are known as functioned effectively in detecting and restoring shades. Otsu's thresholding technique to detect clouds, we replaced those detective shades by using experimental and reference images. In accurate assessment, the overall accuracy and kappa coefficients were about 85% and 0.7128, respectively. This indicates that the proposed technique is effective for recovering the original land surface.

Estimation of Water Quality using Landsat 8 Images for Geum-river, Korea (Landsat 8 이미지영상을 이용한 영양염류농도 추정; 금강을 대상으로)

  • Lim, Jisang;Baik, Jongjin;Kim, Hyunglok;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.48 no.2
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    • pp.79-90
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    • 2015
  • In this study, the water quality parameters of Geum-river were estimated using Landsat 8 satellite image data which had launched in March 2013. The goal of this research is to predict HAB and to monitor spatial pattern of total nitrogen (TN) and total phosphorus (TP) because both TN and TP are the dominant factors of the growth of harmful algal blooms (HABs). To investigate the relationship between satellite band reflectance and in situ measurement value, Pearson' correlation coefficient analysis was used. The band2, 3, 4 and 5 reflectance values among 11 bands of Landsat 8 were used which was highly associated with detecting TN and TP. The 20 in situ data set with satellite's overpass time were identified. TN showed positive relation with band 2 (0.48), band3 (0.62), band4 (0.57) at a significance level of p<0.05. TP also showed high correlation for band2 (0.59), band3 (0.59), band4 (0.58) at a significance level of p<0.01. The optimal regression equation models were constructed for TN and TP based on multiple regression equations. The estimated concentration based on derived regression equations of TN and TP were compared with in situ measurement data. Finally, the spatial pattern of the two parameters was able be monitored through mapping on November 12, 2013 and April 21, 2014.

Detection of Surface Water Bodies in Daegu Using Various Water Indices and Machine Learning Technique Based on the Landsat-8 Satellite Image (Landsat-8 위성영상 기반 수분지수 및 기계학습을 활용한 대구광역시의 지표수 탐지)

  • CHOUNG, Yun-Jae;KIM, Kyoung-Seop;PARK, In-Sun;CHUNG, Youn-In
    • Journal of the Korean Association of Geographic Information Studies
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    • v.24 no.1
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    • pp.1-11
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    • 2021
  • Detection of surface water features including river, wetland, reservoir from the satellite imagery can be utilized for sustainable management and survey of water resources. This research compared the water indices derived from the multispectral bands and the machine learning technique for detecting the surface water features from he Landsat-8 satellite image acquired in Daegu through the following steps. First, the NDWI(Normalized Difference Water Index) image and the MNDWI(Modified Normalized Difference Water Index) image were separately generated using the multispectral bands of the given Landsat-8 satellite image, and the two binary images were generated from these NDWI and MNDWI images, respectively. Then SVM(Support Vector Machine), the widely used machine learning techniques, were employed to generate the land cover image and the binary image was also generated from the generated land cover image. Finally the error matrices were used for measuring the accuracy of the three binary images for detecting the surface water features. The statistical results showed that the binary image generated from the MNDWI image(84%) had the relatively low accuracy than the binary image generated from the NDWI image(94%) and generated by SVM(96%). And some misclassification errors occurred in all three binary images where the land features were misclassified as the surface water features because of the shadow effects.