One dimensional-two dimensional dynamic programming matching algorithm for character recognition

Dynamic programming based one dimensional-two dimensional adaptive pattern matching methods were investigated. In these methods, the reference pattern is represented as a sequence of directional vectors and the input pattern as two dimensional dot pattern. The input pattern needs no preskeletization or local feature analysis, and thus stroke order free top-down pattern matching is carried out. As the starting point, Rubber String Matching algorithm using fixed direction vectors was newly investigated. At latter stages, the reference pattern vectors were permitted some freedom in their directions to cope with abrupt aberrations in input pattern line segments, improving the flexibility of matching. Two cases were considered, allowing 45° and approximately 20° deviations from the vector directions. The 20° version gave the best recognition score.