US Patent 10496809 Generating a challenge-response for authentication using relations among objects

Aspects described herein may allow for the application of generating captcha images using relations among objects. The objects in ground-truth images may be clustered based on the probabilities of co-occurrence. Further aspects described herein may provide for generating a first captcha image comprising a first object and a second object, and generating a second captcha image based on the first captcha image by replacing the first object with the third object. Finally, the first and second captcha images may be presented as security challenges and user access requests may be granted or denied based on responses to the security challenges.