Fig. 1. Integrated design scheme for common optical path of imaging spectrometer and array camera

Fig. 2. Volume phase holographic Bragg diffraction grating

Fig. 3. Working principle of PGP structure imaging spectrometer

Fig. 4. Image geometry relationship between imaging spectrometer and array camera

Fig. 5. Schematic of optical structure of telescope

Fig. 6. Design results of telescopic optical system. (a) MTF curves of telescopic optical system; (b) distortion curves of telescopic optical system; (c) chromatic aberration curves of telescopic optical system

Fig. 7. PGP splitter structure

Fig. 8. Schematic of optical structure of spectral imaging system. (a) 2D optical structure diagram; (b) 3D optical structure diagram

Fig. 9. MTF curves of spectral imaging system in different bands. (a) 400 nm; (b) 700 nm; (c) 1000 nm

Fig. 10. Schematic of integrated optical structure

Fig. 11. MTF curves of PGP imaging spectrometer in different bands. (a) 400 nm; (b) 700 nm; (c) 1000 nm

Fig. 12. RMS wavefront difference of system varies with wavelength

Fig. 13. Prototype of PGP imaging spectrometer

Fig. 14. Spectral calibration in laboratory. (a) Laboratory spectral calibration; (b) 420 nm spectral line; (c) 680 nm spectral line; (d) 980 nm spectral line

Fig. 15. Front cut-off filter. (a) Schematic diagram; (b) spatial position

Fig. 16. Spectral images of different bands. (a) 400 nm; (b) 600 nm; (c) 800 nm; (d) 1000 nm

Fig. 17. Spectral image after stitching

Fig. 18. Reflectance spectra of hyperspectral data cubes and regions of interest. (a) Hyperspectral data cube; (b) reflectance spectra of region of interest

Fig. 19. Automatic geometric correction process

Fig. 20. UAV hyperspectral images and geometric correction results. (a) Original line-array hyperspectral image; (b) hyperspectral image after initial correction using low-precision POS; (c) area array image; (d) self-corrected hyperspectral image