Evaluation of Binarization Methods for Aged Printed Myanmar Documents

Abstract

Binarization is one of sub phases ofpreprocessing step of optical character recognition(OCR). Binarization is separation of foreground textfrom background of document image. The accuracyof OCR mainly relies on binarization’s result. Thispaper compares several alternative binarizationalgorithms for aged printed Myanmar documents.The algorithms evaluated are global thresholding(Otsu), Local thresholding (Niblack, Sauvola, Wolf,Feng and Nick). It is found that the binarized imagesmore stable if filters (Wiener and Gaussian) are priorused before applying binarization algorithms.Another one is that local thresholding is suit for agedMyanmar documents. Among local thresholding,Niblack, Sauvola and Wolf are the more suitablealgorithms based on the experimental results. Thequality of binarized images is verified by usingdifferent assessment parameters like mean squareerror (MSE), signal to noise ratio (SNR) and peaksignal to noise ratio (PSNR). This work aims to getthe high accuracy of recognition steps with the mainobjective of developing OCR of aged printedMyanmar documents