Gabriel Moy, Nathan Jones, Curt Harkless, Randall Potter. Distortion Estimation Techniques in Solving Visual CAPTCHAs. In 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2004), with CD-ROM, 27 June - 2 July 2004, Washington, DC, USA. pages 23-28, IEEE Computer Society, 2004. [doi]
Abstract is missing.