Radiometric and spectral stray light correction for the Portable Remote Imaging Spectrometer (PRISM) coastal ocean sensor

The airborne Portable Remote Imaging Spectrometer (PRISM) instrument is based on a fast (F/1.8) Dyson spectrometer
operating at 350-1050 nm and a two-mirror telescope combined with a Teledyne HyViSI 6604A detector array. Raw
PRISM data contain electronic and optical artifacts that must be removed prior to radiometric calibration. We provide an
overview of the process transforming raw digital numbers to calibrated radiance values. Electronic panel artifacts are first
corrected using empirical relationships developed from laboratory data. The instrument spectral response functions (SRF)
are reconstructed using a measurement-based optimization technique. Removal of SRF effects from the data improves
retrieval of true spectra, particularly in the typically low-signal near-ultraviolet and near-infrared regions. As a final step,
radiometric calibration is performed using corrected measurements of an object of known radiance. Implementation of the
complete calibration procedure maximizes data quality in preparation for subsequent processing steps, such as atmospheric
removal and spectral signature classification.