Method for dating old handwritten manuscripts based on spectral photometry of ink in near infrared range

摘要

Several problems of spectral photometry analysis of handwritten documents have been studied like combined reflection from the both ink and paper material impregnated by ink, the illumination spatial non-uniformity with small light intensity, flexibility and instability of paper sheets. The images acquired at different wavelengths were spatially matched using developed computer algorithm and then regions of interests, i.e. ink lines were extracted. Then reflection spectra obtained at all pixels of ink lines were composed in vector representation, and comparison of the vectors was conducted. As the result, degree of correspondence between different fragments of text has been evaluated. The optical setup and its calibration procedures are considered in detail as well as results of image processing, matching, segmentation and spectral photometry evaluation of ink. Experimental results of different text fragments matching and estimates of text fragments spectral correspondence degree are presented and discussed.