Hyperspectral imaging: potential in non-destructive analysis of palimpsests

Palimpsests -twice written manuscripts- are of great interest since they may contain important hidden text underneath the visible one. Hyperspectral imaging may aid the expert to read the old script by enhancing the contrast between the under- and -overwriting. We present a hyperspectral imager (MUSIS), capable of acquiring 34 calibrated spectral bands in the range of 360-1150 nm (extended to 1550 nm when coupled with a photocathode tube). The potential of spectral imaging to improve the readability of manuscripts by employing common spectral analysis techniques is explored. Results on different manuscripts obtained by principal component analysis (PCA) and linear spectral mixture analysis (LSMA) prove that hyperspectral imaging tools has the potential to become an indispensable tool for the analysis of old manuscripts.