Radiometric Calibration of a UAV-Mounted Hyperspectral Snapshot Camera with Focus on Uniform Spectral Sampling

Small and lightweight hyperspectral cameras mounted on unmanned aerial systems (UAS) are increasingly used as close range remote sensing systems. When they are applied to studies of biophysical parameters in environmental sciences, user have to consider the radiometric response of the imaging sensor and apply necessary corrections to get unbiased parameter estimates. In this paper we discuss the radiometric characteristics of a hyperspectral snapshot camera and a proper vicarious calibration method. We observe that spectral sampling of each pixel of the camera is individually distorted with respect to the nominal values. These errors must be corrected, since they directly affect the parameter retrieval. We provide a simple method to estimate and correct the spectral sampling of each pixel. With correction of the spectral sampling and additional flat fielding, the precision of estimated water quality parameters can be significantly enhanced.