Image processing for compound documents

Until recently, a lot of document image processing (DIP) research has concentrated on the recognition of characters and shapes in document. Whilst the problems of text only based documents have largely been solved, there is a greater need to address the image processing problems posed by mixed-media or multimedia documents. Such documents, commonly referred to as compound documents containing a mixture of text, graphics, line-art, sound annotation, images etc. produce the problem of distinguishing the type of image processing required and in what sector of the document. This paper discusses the processes involved in transforming paper documents into electronic format and gives an example of an application involving the transformation of circuit diagrams to electronic CAD (ECAD) format.