Do-it-yourself VIS/NIR pushbroom hyperspectral imager with C-mount optics

Abstract

This paper describes a new optomechanical design based on a previously presented do-it-yourself pushbroom hyperspectral imager (HSI) using commercial off-the-shelf (COTS) components. The new design uses larger aperture C-mount at F/2.8 instead of S-mount optics at F/4 to increase the throughput, which allows imaging at lower light levels. This is especially useful for dark surfaces like the deep ocean. The improved throughput is 6.77 higher at the center wavelength of 600 nm, which is shown both by theoretical calculations and experimental data. The measured full width at half maximum (FWHM) at 546.1 nm is 3.69 nm, which is close to the theoretical value of 3.3 nm, and smile and keystone are shown to be reduced in the new design. A method to characterize and remove second order effects using a cut-off filter is also presented and discussed.