On the segmentation of touching characters

In many OCR systems, character segmentation is a necessary preprocessing step for character recognition. It is a critical step because incorrectly segmented characters are not likely to be correctly recognized. The most difficult cases in character segmentation are broken characters and touching characters. The problem of segmenting touching characters in various fonts and size in machine-printed text is addressed. The author classifies the touching characters into five categories: touching characters in fixed-pitch fonts, proportional and serif fonts, ambiguous touching characters, and strings with broken and touching characters. Different methods for detecting multiple character segments and for segmenting touching characters in these categories are developed. The methods use features of characters and fonts and profile models.<>