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SRS-99 be — essem SRS-80 - —~— SRS-75 —— SRS-60 - - - SRS-50 —— —-——_—$_——— SRS-40 f° /Meenlepherical % Reflectance / | | 104" szültem —————— = SRS-20 — ———— — SRS-10 — a SRS-05 ) | = ,RS-02 nw 400 4400 400 1000 1200 1400 tex 1600 noe 2200 2400 Aw) Wavelength (nm) Figure 2-18. The reference grey scale (Spectralon) and their reflectance spectra.*° The grey scale shows constant reflectance in the UV-VIS-IR sensitivity range of a silicon-based CCD/CMOS sensor. Spectralon diffuse reflectance standards are manufactured by Labsphere”’ and are available individually, with typical reflectance values ranging from 2% to 99%, and are also available in sets. Although the inclusion in the frame of a number of these standards within this range is considered beneficial and would be recommended, it is realized that these are not inexpensive items. The minimum requirement in order to carry out the post-processing methods proposed is thus the 99% Spectralon diffuse reflectance standard (Figure 2-19). Figure 2-19. The 99% Spectralon diffuse reflectance standard." The Spectralon diffuse reflectance grey scale is not commercially available at present and is custom-made, from patches of Spectralon material from the following reflectance values (white to black); 99%, 75%, 60%, 50% 20%, 10% (two of these) and 2%. Version No. 1.0 58 Date : 14/10/2013
