International Journal of Image Processing and Vision Science


CAPTCHA stands for Completely Automated Public Turing Tests to Tell Computers and Humans Apart. The CAPTCHAs have been widely used across the Internet to defend against undesirable and malicious bot programs. It was observed that an alarming number of CAPTCHAs could be broken by the technique of Image Processing and Artificial Neural Network. Many Researchers have tried to break a CAPTCHA so as to design robust CAPTCHA , but it is essential to generate a strong CAPTCHA that will resist bot attack. This paper has proposed algorithm to analyze the strength of CAPTCHAs using simple image processing techniques such as Preprocessing, Segmentation and Character recognition which in turn helps to improve the robustness and usability of CAPTCHA in Internet System. The experimental result shows the proposed algorithm gives 75 % accuracy to analyze the strength of CAPTCHA.





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