Similar handwritten devanagari character recognition by critical region estimation

The recognition of handwritten similar shape characters are still a challenging problem in HOCR system. Almost entire scripts are suffering with this kind of problem. This manuscript is considered the similar shape character problem in Devanagari script. An algorithm is proposed first to estimate the similar character pairs in Devanagari Script and 7 pairs are identified by investigating the confusion matrix. Similar shape characters have very minor difference in shape that's why at the time of recognition (classification) phase, classifier is being confused with another similar shape characters. This problem can be solved by estimate that minor difference called critical region in the similar shape characters and used critical region to extract the more features before classification phase. The critical region is estimated by Fisher discrimination function. A new kind of masking techniques used to extract the features from ISIDCHAR (standard Devanagari database) and 96.58 % recognition rate is obtained finally after getting the 81.94% improvement in similar character recognition.