Security and Communication Networks / 2017 / Article / Tab 7

Review Article

A Survey on Breaking Technique of Text-Based CAPTCHA

Table 7

Comparisons of segmentation methods.

Segmentation methodsMain basis Character featuresExplanation
AdhesionSkewDistortionOverlap

Segmentation based on individual characterCharacter projection×××Suit strings with little adhesion rather than serious distorted, overlapped strings
Connected components××Limited to overlapping rather than distortion
Character width×××Limited to severely distorted
Character feature×××Effective when character feature is notable and discriminant
Character contour×Applied to the individual character with clear contour

Segmentation base on character componentsCharacter structureOnly when character structure is easy to segment
FilterWide application; the subsequent processing is complex