Recovery of handwritten text from the diaries and papers of David Livingstone

摘要

During his explorations of Africa, David Livingstone kept a diary and wrote letters about his experiences. Near the end of his travels, he ran out of paper and ink and began recording his thoughts on leftover newspaper with ink made from local seeds. These writings suffer from fading, from interference with the printed text and from bleed through of the handwriting on the other side of the paper, making them hard to read. New image processing techniques have been developed to deal with these papers to make Livingstone's handwriting available to the scholars to read. A scan of the David Livingstone's papers was made using a twelve-wavelength, multispectral imaging system. The wavelengths ranged from the ultraviolet to the near infrared. In these wavelengths, the three different types of writing behave differently, making them distinguishable from each other. So far, three methods have been used to recover Livingstone's handwriting. These include pseudocolor (to make the different writings distinguishable), spectral band ratios (to remove text that does not change), and principal components analysis (to separate the different writings). In initial trials, these techniques have been able to lift handwriting off printed text and have suppressed handwriting that has bled through from the other side of the paper.