태양광 정반사가 발생한 CASI-1500 영상을 이용한 근적외선 분광적 특성 분석

Abstract

The specular reflections of sky radiances on the sea surface or so-called sun glints severely distort images. The sun glints correction is needed to be proceeded in prior for better and objective analysis. Many studies have published papers regarding the sun glint correction of high-resolution images using near infrared (NIR) signals due to its characteristic of high water absorption. NIR spectral characteristics are worth of analysis since it is one of the main factor that is utilized for the process of the sun glint correction of high-resolution images. However, the correction methods have been constantly an issue since the results show over-correction and high dependence on sampling. Therefore in this study we firstly analyzed the spectral characteristics of sun glints in NIR section using CASI-1500 data as a preliminary study and proceeded to the development of alternative sun glint correction method. The CASI-1500 data is the airborne hyperspectral sensor image taken at coastal area near Sin-Cheon, Jeju Island, South Korea on October 12, 2013. The analysis was done by comparing basic statistics and histograms of each band and false color composite using NIR band. The spectral characteristics of radiance and reflectance at five wavelengths (744nm, 758nm, 772nm, 786nm, and 801nm) in the NIR band are compared under different conditions. These conditions include (1) sand bottom with difference water depths, (2) ben regarding the sun glint correction of high-resolution images using near infrared (NIR) signals due to its characteristic of high water absorption. NIR spectral characteristics are worth of analysis since it is one of the main factor that is utilized for the process of the sun glint correction of high-resolution images. However, the correction methods have been constantly an issue since the results show over-correction and high dependence on sampling. Therefore in this study we firstly analyzed the spectral characteristics of sun glints in NIR section using CASI-1500 data as a preliminary study and proceeded to the development of alternative sun glint correction method. The CASI-1500 data is the airborne hyperspectral sensor image taken at coastal area near Sin-Cheon, Jeju Island, South Korea on October 12, 2013. The analysis was done by comparing basic statistics and histograms of each band and false color composite using NIR band. The spectral characteristics of radiance and reflectance at five wavelengths (744nm, 758nm, 772nm, 786nm, and 801nm) in the NIR band are compared under different conditions. These conditions include (1) sand bottom with difference water depths, (2) ben