A new two-stage scheme for the recognition of Persian handwritten characters

In this paper, a two-stage scheme for the recognition of Persian handwritten isolated characters is proposed. In the first stage, similar shaped characters are categorized into groups and as a result, 8 groups are obtained from 32 Persian basic characters. In the second stage, the groups containing more than one similar shape characters are considered further for the final recognition. Feature extraction is based on under sampled bitmaps technique and modified chain-code direction frequencies. For the first stage features, we compute 49-dimension features based on under sampled bitmaps from 49 non-overlapping 7 × 7 window-maps. 196-dimension chain-code direction frequencies from 49 overlapping 9 × 9 window-maps are computed and used as features for the second stage of the proposed scheme. Classifiers are one-against-other support vector machines (SVM). We evaluated our scheme on a standard dataset of Persian handwritten characters. Using 36682 samples for training, we tested our scheme on other 15338 samples and obtained 98.10% and 96.68% correct recognition rates when considered 8-class and 32-class problems, respectively.