The imaginary refractive index k and the model r.e-constructed reflectance spectra for the Olivenza grains with two size distributions. Results in (a) and (b) were generated using the CPRMS method, while those in (c) and (d) were generated using the ABS method. (a) k obtained by using the CPRMS matching method. (b) Comparisons of the model spectra and the RELAB spectra. The model spectra were obtained using k shown in (a) and (D₁ = 45 μm, D₂ = 125 μm) that returned the minimum CPRMS value. (c) k obtained by using the CPRMS matching method. (d) Comparison of the model spectra and the RELAB spectra. The model spectra were obtained using k shown in (c) and (D₁ = 120 μm, D₂ = 315 μm) that returned the minimum ABS value.