Fadoua Drira Frank Le Bourgeois Hubert Emptoz Restoring Ink Bleed-Through Degraded Document Images Using a Recursive Unsupervised Classification Technique. 38-49 2006 conf/das/2006 Document Analysis Systems http://dx.doi.org/10.1007/11669487_4 db/conf/das/das2006.html#FadouaBE06