Validation of Airborne Hyperspectral Imagery from Laboratory Panel Characterization to Image Quality Assessment: Implications for an Arctic Peatland Surrogate Simulation Site

摘要

Calibration/validation (cal/val) practices applied to airborne hyperspectral imagery of Arcticregions were developed and assessed as an integrated up-scaling methodology that considers:(ⅰ) calibration of a laboratory reflectance reference panel; (ⅱ) cross-calibration of multiplefield panels; (ⅲ) quality assurance checks of field spectroscopy data; and, (ⅳ) comparison ofresults with airborne hyperspectral imagery. Overall errors of up to 27% were reduced to<4% using these methods. Calibration results of the laboratory panel provided an improvementof 1% in the visible, near and lower shortwave infrared regions with respect to bestestimates achievable using manufacturer supplied calibration data. This improvement wastransferred to field panels using an in-house cross-calibration approach that also allowedpanels to be assessed for degradation that occurs during field deployment. Comparison ofthe field spectroscopy results of four cal/val targets with hyperspectral imagery followingatmospheric correction identified discrepancies from 1% to 4% (absolute) between 450nmand 1050 nm, with errors as high as 27% at lower wavelengths. Application of scene-basedrefinements using two cal/val targets reduced this error across the entire spectral range(<4%) with the most significant improvements below 500 nm. These methods also haveimportant implications to satellite image analysis, especially in Arctic and northern regions.