PT Journal AU Marçal Rusiñol Josep Llados Gemma Sanchez TI Symbol Spotting in Vectorized Technical Drawings Through a Lookup Table of Region Strings SO Pattern Analysis and Applications JI PAA PY 2010 BP 321 EP 331 VL 13 IS 3 DI 10.1007/s10044-009-0161-2 AB In this paper, we address the problem of symbol spotting in technical document images applied to scanned and vectorized line drawings. Like any information spotting architecture, our approach has two components. First, symbols are decomposed in primitives which are compactly represented and second a primitive indexing structure aims to efficiently retrieve similar primitives. Primitives are encoded in terms of attributed strings representing closed regions. Similar strings are clustered in a lookup table so that the set median strings act as indexing keys. A voting scheme formulates hypothesis in certain locations of the line drawing image where there is a high presence of regions similar to the queried ones, and therefore, a high probability to find the queried graphical symbol. The proposed approach is illustrated in a framework consisting in spotting furniture symbols in architectural drawings. It has been proved to work even in the presence of noise and distortion introduced by the scanning and raster-to-vector processes. ER