Comparison of parsing algorithms for recognizing online handwritten mathematical expressions

Parsing process is the most important process in recognition of online handwritten mathematical expressions. There are two basic approaches: stroke order dependent (SOD) and stroke order free (SOF) approaches. The SOD approach depends on stroke order while the SOF approach is free from stroke order. Although both approaches have shown high recognition rates in recently competitions, there are a few of works that analyze the complexities of parsing algorithms in the same experimental conditions. In this work, we have tested and analyzed recognition rate, recognition speed and memory space required by parsing algorithms on CROHME 2014. SOF is slightly superior to SOD in recognition rate, but SOD is faster in processing time and lower in memory space than SOF.