Separation of single- and double-touching handwritten numeral strings based on structural analysis

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)514-522
Journal / PublicationOptical Engineering
Issue number1-3
Publication statusPublished - Mar 1999


We develop a new method to separate touching handwritten numeral pairs using structural analysis. The string is preprocessed with an efficient algorithm for smoothing, linearization, and detection of structural points of image contours. The structural region of the string is determined. Some left- or right-side numerals of the string are recognized. The property of each hole contour in a string is detected. The touching model of a string is determined, whether single- or double-touching. For double-touching, the touching hole contour is determined. For the two touching models, the touching point is preselected, its position is corrected, and the corresponding match touching point is found. The string is separated based on all touching points. All processing procedures are based on morphological structural analyses. We have tested our method on image samples taken from the U.S. National Institute of Science and Technology (NIST) database. We used 500 sample images to design the required models. For 3287 test samples the correct-separation rate was 97.2% for single-touching strings, and 97% for double-touching strings. © 1999 Society of Photo-Optical Instrumentation Engineers.

Research Area(s)

  • Character recognition, Morphological structure of character strings, Separation of numeral strings, Structural features, Touching handwritten numeral strings

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