A method is described for reconstructing decorative images concealed by layers of overcoatings. The method employs a nonparametric multivariate algorithm and a cellular-automaton construct to convert the near-infrared spectrum of a surface into digital images of the surface layers. The technique is potentially applicable to thé restoration of historic buildings where aging, previous restoration attempts, and even political considerations have resulted in the alteration of the original historic surfaces.
Robert A. Lodder and Gary M. Hieftje, "Subsurface Image Reconstruction by Near-Infrared Reflectance Analysis," Appl. Spectrosc. 42, 309-312 (1988)