Restoring high-resolution text images to improve legibility and OCR accuracy

摘要

A new method for restoring high-resolution binary images is presented to improve legibility and OCR accuracy for low-resolution text images. The initially restored image is generated by simple techniques, and is then improved by integrating a variety of features obtained through image analysis. Missing strokes of characters are complemented based on topographic features. Contours of characters are then modified in terms of gradient magnitudes and curvatures along the contours. Finally, contours are beautified so that they look good to the human eye. The proposed method can deal with characters having complex structures such as Kanji, and entails relatively simple computation. Through experiments, it has been validated that the proposed method improves both OCR accuracy and legibility. In particular, smoothness and linearity along contours are significantly unproved and strokes are restored correctly.