Flatfielding in spatial heterodyne spectroscopy

Spatial heterodyne spectroscopy (SHS) is a Fourier-transform spectroscopic technique that simultaneously records all path differences using a detector array. Compared to conventional Fourier-transform spectroscopy that measures interferogram samples sequentially in the time domain, SHS is insensitive to a changing scene; however, the effects caused by differences in the detector elements and/or the optics for each sample must be addressed with a flatfield correction. The flatfield correction is typically a characteristic of the instrument and does not change with the observed scene. We present three different flatfielding approaches. Each is based on different assumptions and is applicable depending on the instrumental effects dominating the flatfield.