On-line handwritten flowchart recognition based on logical structure and graph grammar

Abstract

Although sketch recognition has been studied for dozens of years, the recognition of two dimensional online documents is still a challenging problem of pattern recognition. This paper deals with this problem depending on the logical structure of the sketch and a graph grammar. The recognition process consists of three stages. First, we use the dynamic programming to group the stroke sequence into stroke combinations. Then, we get the candidate symbols from a classifier of the Random Forest algorithm. Finally, a graph grammar is used to describe the logical structure of the flowchart. This method has been applied to flowcharts of a freely available database. Although 23.2% of the candidate symbols are misclassified, we still achieve an average accuracy of 70.4%, which demonstrate the effectiveness and efficiency of our approach.