Accessibility & the Web | News

Towson U Tackles Audio CAPTCHA

• By Dian Schaffhauser
• 03/23/11

A team of instructors and students at Towson University is trying to build a better CAPTCHA mousetrap. The group recently received a $50,000 grant for the work from the Maryland Technology Development Corp., a publicly funded state technology transfer and development group.

CAPTCHA, or "Completely Automated Public Turing test to tell Computers and Humans Apart," is a Carnegie Mellon University-developed utility typically found on Web sites that require some level of interaction to perform a task, such as download a report or access a special page. CAPTCHA asks a visitor to spell out the letters shown in a distorted image to prove he or she is human and not a bot or virus performing some automated activity.

Multiple versions of CAPTCHA are in use, but they tend to share one flaw: They rely on the ability of the visitor to read the characters, which prevents blind users from being able to interact with the program. Although CAPTCHA often includes an audio option based on English language recordings, that too shows a low success rate among blind users, according to the university.

It's the audio approach that the Towson team is focusing on. SoundsRight is an audio-based version of CAPTCHA that uses recognition of common sounds--bells, a dog barking, or water running. The library of sounds is designed to be recognizable by people of different cultures and backgrounds in order to make the technology usable to the greatest number of potential users.

The National Federation of the Blind has been a long-time partner on the SoundsRight project and has provided design and concept review.

"TU's SoundsRight initiative will provide blind people with equal access to Web sites that utilize CAPTCHAs, and most importantly, allow blind people to access Web sites at the same time as sighted users," said Marc Maurer, president of the federation. "Blind people should not have to use a separate, more time-consuming process to access Web sites that use CAPTCHAs; we deserve and demand the same access as all other users."

The effort is being directed by Jonathan Lazar, a professor of computer and information sciences and director of the Universal Usability Laboratory in the College of Science and Mathematics at Towson. Lazar has been working for a decade to make computers more accessible for people with limited or no vision.

Lazar is partnering with the software development team within the university's Division of Economic and Community Outreach to further develop a prototype. The criteria for the effort is that it be commercially viable, enhance security features, and complete usability testing.

"When Web sites are inaccessible, it's not just an inconvenience," Lazar explained in a university article about his work on accessibility."If you can't get the lowest fare on an airline Web site, if you can't take advantage of Web-only specials on an e-commerce site--it becomes pricing discrimination. If you cannot use the same workplace software tools, communication tools and social-networking software--it becomes social exclusion.... Technology should be a driving force for bringing people together, not increasing existing barriers of discrimination. We have the technical capability, the existing knowledge, to design for accessibility, for inclusion. Why don't we do it?"