Absolute radiometric calibration of the KOMPSAT-2 multispectral camera using a reflectance-based method and empirical comparison with IKONOS and QuickBird images

Abstract

This paper presents absolute radiometric calibration coefficients (gains) that explain the relationship between the digital number (DN) and at-sensor radiance for the multispectral camera (MSC) on Korea's first high-resolution satellite (KOMPSAT-2). Absolute radiometric calibration was performed using a reflectance-based method. In addition, the suitability of vicarious results from radiance-and reflectance-based validations was analyzed with reference to IKONOS and QuickBird images. The latter are spectrally similar to KOMPSAT-2 images and have been validated in a large number of studies. For all bands, the R 2 values of fitted lines for the gain ranged from 0.82 to 0.94, representing an improvement compared to previous findings for the KOMPSAT-2 MSC. To analyze the suitability of the vicarious results, same-pixel at-sensor radiances across different spectral bands were compared. In all bands, except the red band of QuickBird, the at-sensor radiances of KOMPSAT-2 MSC were highly correlated with those of IKONOS and QuickBird. In addition, same-pixel comparisons of reflectance across different spectral bands showed that the slopes of the least-squares lines for each band were similar to the results of the radiance comparison. The standard deviation among top of atmosphere (TOA) reflectances was within 0.019 for all bands. To calculate the tasseled cap transformation (TCT) coefficients for the KOMPSAT-2 MSC, an empirical method was applied using radiometric normalization. The results were similar to those obtained using the TCT coefficients for IKONOS and QuickBird in the brightness, greenness, and wetness components. The TCT images showed similar patterns. The absolute radiometric calibration coefficients presented here appear to be a good standard for maintaining the optical quality of the KOMPSAT-2 MSC, for which prelaunch, on-board, and vicarious calibration data are lacking.

Inter-Band Radiometric Comparison and Calibration of ASTER Visible and Near-Infrared Bands

“…After launch, in-flight calibration was performed by the onboard calibrator every 33 days (originally 17 days; currently 49 days) [11]. The vicarious calibration based on a reflectance-based approach [12][13][14][15][16] has been conducted jointly by Saga University, the University of Arizona and the National Institute of Advanced Industrial Science and Technology, Japan (AIST), over dry lakes in Nevada, U.S.A., such as Railroad Valley Playa and Ivanpah Playa [17]. The cross-calibration with the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra was performed over the vicarious calibration sites [18].…”

Extraction of Water Body Information from Remote Sensing Imagery While Considering Greenness and Wetness Based on Tasseled Cap Transformation

“…For the Gaofen-1 satellite data, no definite coefficient for TCT has yet to be developed; however, by comparing the parameters of the WFV cameras sensor of Gaofen-1 with known satellite sensors with Tasseled Cap transform coefficients, it was found that the WFV sensor and the IKONOS satellite sensor have a similar number of bands and spectral range of bands [59]. As the TCT conversion coefficient is fixed and determined by the band number and band range of a sensor, the conversion coefficient of the IKONOS satellite was selected in this paper (Table 1) [60,61].…”

Radiometric Calibration and Uncertainty Analysis of KOMPSAT-3A Using the Reflectance-Based Method

“…After launching the KOMPSAT series, radiometric calibration and validation was applied to the imagery by the Korean Aerospace Research Institute (KARI) and Pukyong National University (PKNU) [10,11]. This paper examines the laboratory-based prelaunch calibration conducted by KARI, together with the post-launch absolute calibration and cross calibration executed by a tag team of KARI and PKNU scientists during the LEOP.…”