Spectral smile correction in CRISM hyperspectral images

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is affected by an artifact common to pushbroom sensors: ldquospectral smilerdquo. As a consequence, both central wavelength and spectral resolution become dependent on the across-track position thus giving rise to a horizontal spatial modulation. The correction of CRISM spectral smile is addressed using a two-step correction. First, data is re-sampled to the so-called ldquosweet spotrdquo wavelengths. Secondly, the non-uniform spectral response width of the detection elements is overcome by mimicking an increase of resolution thanks to a spectral sharpening. Experiments show remarkable results regarding the decrease of smile energy.