CAPTCHAs based on visual illusions

Simple SummaryContent extracted from patent full text and abstract with AI.

This patent describes a new approach to CAPTCHA security by leveraging visual illusions that are easily perceived by humans but difficult for computer algorithms to emulate. The system generates CAPTCHA images or video sequences which utilize effects such as lightness constancy and motion-defined form (e.g., certain brightness illusions or moving text against a cluttered background). Users are required to solve cognitive tasks—like distinguishing elements based on perceived brightness or tracking symbols moving in unique patterns—to demonstrate their humanity. Such CAPTCHAs exploit inherent strengths of human visual perception that are challenging for bots and machine vision systems to replicate.

Use CasesContent extracted from patent full text and abstract with AI.

• User authentication on websites to block bots (e.g., during account creation, login, or form submission)
• Access control for online resources and digital services
• Preventing automated abuse of online polls, ticketing, and content submission systems
• Securing mobile applications against automated scripts
• Verifying genuine users in online voting or feedback systems

BenefitsContent extracted from patent full text and abstract with AI.

• Increased resistance to automated CAPTCHA-breaking techniques as they exploit human perceptual strengths not easily emulated by machines
• Maintains or improves usability for human users, reducing frustration compared to highly distorted text-based CAPTCHAs
• Can generate a large variety of unique CAPTCHA challenges automatically, enhancing security through randomness
• Applicable to both static images and dynamic video, increasing flexibility and effectiveness
• Potentially improves trust and reduced barrier to entry for legitimate users by making CAPTCHAs more solvable and less annoying

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

CAPTCHAs based on visual illusions are proposed. Validating that a user is a human may be accomplished through various techniques. The invention proposes a method for validating that a user is human using several types of reading-based Captchas that exploit specific capabilities of the human visual system. Perceptions caused by the effect of lightness constancy or grouping phenomena due to transparent motion are hard to emulate algorithmically and provide novel authentication mechanisms. The invention further proposes a device for generating a Captcha image and/or a Captcha video sequence which is adapted for performing the method.