SPECTRAL POLISHING OF HIGH RESOLUTION IMAGING SPECTROSCOPY DATA

Imaging spectroscopy systems covering the visible to the short wave infrared range at wavelength resolutions below 10 nm are more and more used for research and for environmental applications. The compensation for influences of the atmosphere is well solved by inversion of radiative transfer codes as it is done by the ATCOR model or similar methods. However, spectral artifacts remain visible after the atmospheric correction. Current hyperspectral systems such as HySpex, AISA or APEX resolve the spectrum at sampling intervals down to 1-2 nm. Artifacts are usually visible in such data even after optimal correction for spectral smile distortions. The final correction for such artifacts is known as 'spectral polishing'. A variety methods of spectral polishing are tested on sample data sets of the Hyperion and the HySpex imaging spectrometer. Additionally, simulations on artificial data show tradeoffs between information preservation and noise removal in the spectral polishing process. Based on this evaluation, recommendations are given on how to improve spectra by polishing techniques for both coarse and high resolution data. It is then shown, how such techniques are to be included as standard processing steps in higher level data processing chains.