Peter Matthews, Cliff Changchun Zou. Scene tagging: image-based CAPTCHA using image composition and object relationships. In Dengguo Feng, David A. Basin, Peng Liu, editors, Proceedings of the 5th ACM Symposium on Information, Computer and Communications Security, ASIACCS 2010, Beijing, China, April 13-16, 2010. pages 345-350, ACM, 2010. [doi]
Abstract is missing.