The usefulness of a collection of scanned graphical documents can be measured by the facilities available for their retrieval. We present an approach for indexing a collection of line drawings automatically. The indexing is based on the textual and graphical content of the drawings. This approach has been developed to facilitate `retrieval by example' in heterogeneous collections of graphical documents. No a priori knowledge about the application domain is assumed. Starting with a raster image, candidate character patterns and graphical primitives (i.e., line segments and arcs) are extracted. Candidate character patterns are classified by an OCR method and grouped into word hypotheses. Graphical features of various types are computed from groupings of graphical primitives (e.g., sequences of adjacent lines, pairs of parallel lines). Retrieval occurs with a weighted information retrieval system. Each document of the collection and each query are described with a set of indexing features with their corresponding weights. The weight of an indexing feature reflects the descriptive nature of the feature and is computed from the number of occurrences of the indexing feature in the document (feature frequency ff) and the number of documents containing the indexing feature (document frequency df).

Date Published: 23 March 1995
PDF: 12 pages
Proc. SPIE 2420, Storage and Retrieval for Image and Video Databases III, (23 March 1995); doi: 10.1117/12.205287

Published in SPIE Proceedings Vol. 2420:
Storage and Retrieval for Image and Video Databases III
Wayne Niblack; Ramesh C. Jain, Editor(s)