On-line writing-box-free recognition of handwritten Japanese text considering character size variations

An on-line writing-box-free method for recognizing handwritten Japanese text is proposed. This method is achieved by the following procedure. First, the average character size of input handwritten text is estimated. Second, candidates for character segmentation are detected using geometric features between two adjacent strokes. Finally, a search is performed by dynamic programming (DP) for the string that maximizes evaluation score (acceptability as Japanese text). The evaluation score reflects the likelihood of character segmentation, recognition, context and the size of each character. The size is a newly introduced factor since alphabets, numerals, symbols, Japanese phonetic characters, simple Chinese characters and compound Chinese characters are all written in different sizes even in a single line of text. Experimental results show that the incorporation of the character size likelihood increases the character recognition rate for Japanese text.