In this video, Google research scientist Luis von Ahn presents an innovative service Google call reCAPTCHA. It is essentially a reimagining of the CAPTCHA security protocol to make it more useful. 


The original process should be familiar to most people: a garbled image is presented and users must type the alphanumeric code correctly in order to pass through. This typically takes 10 seconds to complete. Although this may not seem much, it adds up to thousands of wasted hours when multiplied by the millions of times people do it around the world.


Google wanted to make those hours count and so reCAPTCHA was born. Instead of providing random garbled images, reCAPTCHA uses scanned texts from digitizing efforts of various libraries. Sometimes optical character recognition software cannot recognize the letters but humans can quickly identify the patterns. This ideal arrangement helps the archives finish more books in less time.


This service is provided for free by Google so anyone can install it on their site quite easily. The images come directly from the company’s servers to ensure that everything is centralized and secure. Measures have been put in place to prevent spammers from gaming the system.