Impact of scene changes during data acquisition in Fourier spectroscopy

The impact of changes of the spectral radiance in a Fourier transform spectrometer's field of view (FOV) during recording time of an interferogram is examined. Particularly systematic changes, with a time constant which is in the order of the time required to record one interferogram, are of interest here. Both an analytic and a simulative approach is made to examine the impact on the measured spectrum. Airborne measurements of fire scenes are a typical example where changes of spectral radiance during data acquisition time are inevitable. In such cases, flight velocity causes the scene in the spectrometer's FOV to change continuously, and the scene elements (fire, for example) might be expected to be dynamical even by themselves.