Calibration of inexpensive pushbroom imaging spectrometers

We demonstrate the calibration and error estimation for three inexpensive p ushbroom imaging spectrometers that operate in the visible/near-infrared ra nge. The instruments were all built at the Naval Research Laboratory from c ommercial, off-the-shelf components. Although they are similar in basic des ign, their differences reflect the different objectives for which they were built. Each camera presents specific difficulties in calculating correctio ns 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 t he other instruments, equipped with an intensifier, are dominated by camera noise.