Three-stage handwriting stroke extraction method with hidden loop recovery

A method for extraction of strokes from handwriting characters and graphemes is presented. The method allows the modelling of the original pen tip trajectory close to that perceived by humans, thus allowing its use in writer identification and verification tasks. The method is also capable of identifying retraced strokes and recovering hidden loops. Strokes are represented as cubic splines. The method extracts strokes in three stages: vectorisation, merging of skeletal branches and loop recovery, and final adjustment of near-junction and loop pieces. The evaluation of the method is performed by using its results for structural feature extraction and writer classification based on the features.