Design Of An Imaging Spectrometer Based On Prism-grating-prism Dispersive Element

Hyperspectral imaging technology is an important means of remote sensingtechnology, with the development of hyperspectral technology and expansion ofremote sensing applications, imaging spectrometer systems with the features ofcompact structure, low cost and modular production is needed so much. So far, themost widely used type of imaging spectrometer is the dispersive, especially imagingspectrometer based on a diffraction grating is more mature. But imaging spectrometerbased on plane diffraction grating mostly have off-axis optical paths, structure iscomplicated and difficult to align; while imaging spectrometer used concave gratingor convex grating have concentric structures, grating manufacturing is difficult, rasterprocessing effects on instrument performance greatly. These spectrometers have littlepotential in civilian market. Because PGP spectroscopic device manufacturing issimple, performance is stable, diffraction efficiency is relatively high, PGP-basedimaging spectrometer structure is relatively simple, great potential in small, modularand cost aspects of surveying and mapping in the aerospace, industrial monitoring andmicroscopy applications there are areas of great development in recent years this kindimaging spectrometers become a research focus.Based on the work and design principles dispersive spectrometer, based prism-grating-Prism combination of spectroscopic devices, designed a PGP imagingspectrometer system, its spatial resolution is better than1mrad, field of view is16°,covering400nm~1000nm spectral range, spectral resolution is better than3nm. Themodular design principle, pre-telescope system and spectral splitting system designedrespectively, for the sake of simplicity structure, the system uses the refractivestructure, spectral imaging system spectral components using a prism-grating-prismstructure, and to ensure that the direct-vision.In order to have a better understanding of PGP imaging spectrometer system,according to the laboratory conditions, using the V10type PGP spectroscopic systemsand IO Flare4M180CMOS camera, imaging spectrometer assembled,that spatialresolution is2mrad, reaching22°field of view, spectral range is450nm~950nm,spectral resolution is6nm. On the basis of spectral and radiometric calibration theory,full spectral spectral calibration was conducted using a monochromator,results showthat the system is a good linear dispersion, the center wavelength of the standard deviation of0.45nm, the average spectrum resolution of6.393nm, spectral resolutionstandard deviation0.198nm, curved lines in the sub-pixel range. With characteristiclines scaling method results and full spectral calibration scans obtained werecompared between the two standard deviation of0.58nm, the higher the degree ofmatching two calibration results obtained by the method described spectral calibrationresults and high reliability. Radiometric calibration was conducted using anintegrating sphere system, radiometric calibration error is controlled within4.35%,and the average spectral response curve of the system is plotted. Then the outfieldpush-broom was conducted with the spectrometer on a rotating platform, and theshape of resulting curve matches the radiometric curve resulted from standardradiometric meter very well, which shows that the performance of the PGP imagingperformance imaging spectrometer system meet the actual use.