Distortion estimation techniques in solving visual CAPTCHAs

G. Moy, N. Jones, C. Harkless, R. Potter
Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004.  
This paper describes two distortion estimation techniques for object recognition that solve EZ-Gimpy and Gimpy-r, two of the visual CAPTCHAs ("Completely Automated Public Turing test to tell Computers and Humans Apart") with high degrees of success. A CAPTCHA is a program that generates and grades tests that most humans can pass but current computer programs cannot pass. We have developed a correlation algorithm that correctly identifies the word in an EZ-Gimpy challenge image 99% of the time
more » ... d a direct distortion estimation algorithm that correctly identifies the four letters in a Gimpy-r challenge image 78% of the time.
doi:10.1109/cvpr.2004.1315140 fatcat:3mg2a7ifgbavddevs4dtgx6gay