Font Size Independent OCR for Noori Nastaleeq

This paper presents a technique for font size independent OCR of Noori Nastaleeq. Most of the existing OCRs for Noori Nastaleeq support only a single font size. Urdu government documents, news papers, magazines and books written in Noori Nastaleeq font style, has varying range of font sizes. The presented technique in this paper gives support for the font size independence for Noori Nastaleeq OCR, which makes the existing OCR [5] to recognize the Noori Nastaleeq text of different font sizes. The presented technique resizes the input ligature using Splines. Outline of the input ligature is extracted and then scaling factor is applied according to the font size to make the ligature outline to the size at which the existing OCR is trained. The scaled outline is then converted into the image form so that the OCR can recognize it. The presented technique is tested on the Urdu single character ligatures and the recognition rate is 98% for the manually generated data and 96% for the data scanned from different books and magazines. Keywords— OCR, Noori Nastaleeq, Splines.