Fig. 1. Schematic of spectral reconstruction principle and comparison of measurement matrix construction methods. (a) Incident spectrum; (b) simulated soil micropore broadband filter array; (c) detector array; (d) measurement matrix constructed by traditional method; (e) measurement matrix constructed by difference method; (f) schematic of simulated soil micropore

Fig. 2. Simulation process

Fig. 3. Simulated soil micropore filtering structure. (a) Two-dimensional random pores of simulated soil; (b) blurring; (c) sharpening; (d) removal of isolated pores and segmentation; (e) internal pore pattern within the filtering unit; (f) schematic of the simulated soil micropore filtering unit modeling; (g) schematic of the non-porous TiO₂ film modeling; (h) transmission characteristics of micropore 1 and micropore 2; (i) transmission characteristics of micropore 3 and micropore 4

Fig. 4. Impact of difference method on correlation. (a)-(c) Difference results of the transmission characteristics of four adjacent simulated soil micropore filtering units; (d) average correlation coefficients of three plans changed with average area ratio

Fig. 5. Comparison of spectral reconstruction results for three plans. (a) (e) (i) Broadband spectral reconstruction results; (b) (f) (j) narrowband double peak reconstruction results with an 8 nm interval; (c) (g) (k) narrowband double peak reconstruction results with a 3 nm interval; (d) (h) (l) reconstruction error for each spectrum

Fig. 6. Mechanism of simulated soil micropore and difference method