Calibration of inexpensive pushbroom imaging spectrometers

We demonstrate the calibration and error estimation for three inexpensive pushbroom imaging spectrometers that operate in the visible/near-infrared range. The instruments were all built at the Naval Research Laboratory from commercial, off-the-shelf components. Although they are similar in basic design, their differences reflect the different objectives for which they were built. Each camera presents specific difficulties in calculating corrections to achieve uniformity and to convert to physical units. The calibration errors of one instrument are dominated by uncertainties in the integrating sphere, particularly in the short wavelength region. The errors of one of the other instruments, equipped with an intensifier, are dominated by camera noise.