Xiaonan Lu James Ze Wang Prasenjit Mitra C. Lee Giles Automatic Extraction of Data from 2-D Plots in Documents. 188-192 2007 conf/icdar/2007 ICDAR http://doi.ieeecomputersociety.org/10.1109/ICDAR.2007.69 db/conf/icdar/icdar2007.html#LuWMG07