Method and apparatus for screening documents

摘要

A method and apparatus for screening documents such as bank notes 1 for suitability for continued circulation, in which a damage index is computed for each document from a number of factors comprising a shape factor, an orientation factor, a size factor and a location factor developed for each defect in the document. Shape and rotation factors are obtained by applying Fourier and/or Wavelet transforms to sets of contour signals developed on scanning a document for defects using an optical scanner (6). <IMAGE>