Fig. 1. Paper cultural relics foxing detection system

Fig. 2. (a)Part of foxing sample; (b), (c) Super depth of field micrograph

Fig. 3. Paper cultural relics reflection spectrum and average reflection spectrum

Fig. 4. Paper cultural relics feature band image
(a): 464 nm band image; (b): 787 nm band image

Fig. 5. Calculation results of band math of paper cultural relics
(a): 464~767 nm image; (b): 464/767 nm image; (c): 767~464 nm image; (d): 767~464 nm image

Fig. 6. The images of the simulating sample after MNF transformation
(a): MNF-band 1; (b): MNF-band 2; (c): MNF-band 7; (d): RGB image after MNF transformation