Understanding paper documents
We describe the organization and several components of an automated document processing system that begins with digitized images of documents and produces representations at higher levels. Such representations inlcude: the visual sketch (connected components extracted from the background), physical layout (spatial extents of blocks corresponding to text, graphics), logical layout (grouping of strings into words and phrases), and block primitives (e.g., recognised characters and words in text blocks, recognition of hand-drawn line drawings i.e. schematic electronic circuits). We describe algorithms for deriving several of the representations and describe the interaction of different modules. The methods are illustrated with examples.