Fig. 1. Schematic diagram of UAV equipped imaging spectrometer measurement.(a) Panel measurement; (b) Target area measurement

Fig. 2. Schematic diagram of LCIS spectroscopic system

Fig. 3. Image of an off-axis object point on the meridian plane

Fig. 4. Image of an off-axis object point on the sagittal plane

Fig. 5. Schematic diagram of spectroscopic

Fig. 6. Schematic diagram of spectroscopic system imaging in meridian plane system imaging in sagittal plane

Fig. 7. Location of both meridian and sagittal images for different wavelengths

Fig. 8. Functional relationship between $\overline{\phi ΄}$ and $\overline{{\theta }_{\mathrm{3}}}$

Fig. 9. Flowchat of initial structure design calculation for LCIS system

Fig. 10. Optimized optical path diagram of the spectroscopic system

Fig. 11. MTF curves of the spectroscopic system with the wavelength of 400 nm (a), 600 nm (b), 800 nm (c), 1000 nm (d)

Fig. 12. Spot diagram of the spectroscopic system with the wavelengths of 400 nm (a)、600 nm (b)、800 nm (c)、1000 nm (d)

Fig. 13. Aberration images of the spectroscopic system. (a) Smile image; (b) Keystone image

Fig. 14. Optical structure diagram of off-axis three-mirror telescope system

Fig. 15. MTF curves of off-axis three-mirror telescope system in different field of view

Fig. 16. Optical path diagram of LCIS system

Fig. 17. Spot diagram of the LCIS system with the wavelengths of 0.4 µm (a)、0.6 µm (b)、0.8 µm (c)、1 µm (d)

Fig. 18. MTF curves of the LCIS system with the wavelengths of 0.4 µm (a)、0.6 µm (b)、0.8 µm (c)、1 µm (d)

Fig. 19. Encircled energy curves at the wavelength of 0.4 µm (a)、0.6 µm (b)、0.8 µm (c)、1 µm (d)