Review Article
A Survey on Breaking Technique of Text-Based CAPTCHA
Table 2
Comparison of typical methods based on segmentation for breaking nonadherent CAPTCHA.
| Example | Source | Success rate | Reference | Breaking method | Year |
| | Gimpy-r | 78% | [57] | Segmentation: character gap | 2004 | Recognition: distortion evaluation |
| | EZ-Gimpy | 97.9% | [58] | Segmentation: connected region | 2004 | Recognition: distortion evaluation |
| | Captcha-service | 100% | [34] | Segmentation: vertical projection Recognition: statistical character pixels | 2007 |
| | Ego-share | 92.2% | [5] | Segmentation: connected region | 2009 | Recognition: SVM |
| | Ge-Captcha | 100% | [59] | CW-SSIM | 2010 |
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Note. SVM: support vector machine, CW-SSIM: complex wavelet based structural similarity.
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