High-precision and fast spectral distortion measurement of Offner imaging spectrometer

Imaging spectrometers can simultaneously obtain spatial and spectral information of targets with high spectral resolution and high spatial resolution. They are widely used in fields such as resource surveys, environmental monitoring, and mineral exploration. Spectral distortion is directly related to data fidelity and is important indicator for evaluating the performance of imaging spectrometers. It mainly includes two main parameters: smile and keystone. In view of the shortcomings of existing spectral distortion measurement methods, such as low accuracy and low measurement efficiency, this paper proposes a multi-field and multi-band spectral distortion measurement method. This method uses a spectral line lamp to illuminate the periodic line target, and images the periodic line target to the incident slit through the relay system. After passing through the spectroscopic system, the small pixel detector receives its spectral signal, and finally completes the measurement of spectral distortion. Using this method, the spectral distortion of the Offner imaging spectrometer is measured. The smile and keystone are 0.30±0.02μm and 0.26±0.02μm, respectively, and its expanded uncertainty is better than the 0.12μm measured by the standard light source method. Experiments show that the method proposed in the paper can effectively improve the accuracy and efficiency of spectral distortion measurement, and provide a technical basis for further performance evaluation and instrument calibration of imaging spectrometers.