Since computers have trouble reading squiggly words like these, CAPTCHAs are designed to allow humans in but prevent malicious programs from scalping tickets or obtain millions of email accounts for spamming. But there’s a twist — the words in many of the CAPTCHAs provided by reCAPTCHA come from scanned archival newspapers and old books. Computers find it hard to recognize these words because the ink and paper have degraded over time, but by typing them in as a CAPTCHA, crowds teach computers to read the scanned text.
In this way, reCAPTCHA’s unique technology improves the process that converts scanned images into plain text, known as Optical Character Recognition (OCR). This technology also powers large scale text scanning projects like Google Books and Google News Archive Search. Having the text version of documents is important because plain text can be searched, easily rendered on mobile devices and displayed to visually impaired users. So we'll be applying the technology within Google not only to increase fraud and spam protection for Google products but also to improve our books and newspaper scanning process.
That's why we're excited to welcome the reCAPTCHA team to Google, and we're committed to delivering the same high level of performance that websites using reCAPTCHA have come to expect. Improving the availability and accessibility of all the information on the Internet is really important to us, so we're looking forward to advancing this technology with the reCAPTCHA team.
Posted by Luis von Ahn, co-founder of reCAPTCHA, and Will Cathcart, Google Product Manager