Full characterization of spatial coregistration errors and spatial resolution in spectral imagers

For multi- and hyperspectral imagers, the integrity of the spectral information depends critically on the spatial coregistration between bands. There is at present no commonly accepted way to fully specify coregistration performance. This paper shows how a relatively simple measurement technique can be used to form sharp images of the point spread function in all bands, yielding information about spatial coregistration, as well as spatial resolution. A previously proposed metric is applied to characterize coregistration in terms of PSF similarity between bands. Resolution is characterized by ensquared energy. Two commercial hyperspectral cameras with nominally similar specifications are compared, and turn out to have large differences in their actual performance. The results, and the relative simplicity of the measurement, suggest that the method is suitable as a standardized performance test.