The New York Times looks at Captchas, those annoying security features you must defeat before Ticketmaster will release your Justin Bieber tickets. The technology is now being used to reverse decipher Old World fonts. Captchas is short for “completely automated public Turing test to tell computers and humans apart”.
The set of software tools that accomplishes this feat is called reCaptcha and was developed by a team of researchers led by Luis von Ahn, a computer scientist at Carnegie Mellon University…
Digitization is normally a three-stage process: create a photographic image of the text, also known as a bitmap; encode the text in a compact, easily handled and searchable form using optical character recognition software, commonly called O.C.R.; and, finally, correct the mistakes.
Today’s technology makes the first two steps relatively straightforward. The third, however, can be extremely difficult. For vintage 19th-century texts in English, O.C.R. programs mess up or miss 10 percent to 30 percent of the words. Only humans can fix the errors. The standard method, called key and verify, uses two transcribers to type the text independently and compares the results. This is time-consuming and extremely expensive.
But in 2006, Dr. von Ahn’s team figured out a way around this obstacle. The ubiquitous Captchas, familiar to even the most casual Web user, were the perfect tools.
