reCAPTCHA

ReCAPTCHA is a CAPTCHA service, so a method to ensure that a certain action on the internet by a person and is not made by a bot. reCAPTCHA is simultaneously used for digitizing books and magazines.

History

According to an extrapolation of the Carnegie Mellon University to spend worldwide Internet users per day 150,000 hours trying to solve CAPTCHAs. The regularity and gratuitousness of this performance led to the idea of ​​using them for useful purposes. The computer scientist Luis von Ahn, who was instrumental in the invention of CAPTCHA method in 2000, it developed in 2007 a ​​system called reCAPTCHA that of in the book - digitizing scanned words that do not recognize the text recognition software, by entering CAPTCHAs optimized. The system drew its words beginning from a range of Internet Archive, which deals with the digitization of books. In addition, the service helped with the digitization of the archive of all available courses 130 years the New York Times: Within a few months after starting this project in 2009 as 20 vintages were digitized.

September 16, 2009 it was announced that Google has bought the company reCAPTCHA. Google benefits by because it is part of its operating field to digitize books and other printed matter. In March 2012 it was confirmed that Google now reveals even house numbers from Google Street View to optimize the database for Google Maps.

Function and Applications

On each two CAPTCHA words are displayed: one is already known and confirmed the system, the other is an unrecognized word of a digitization project.

The problem of figuring out whether the input of a user is correct, can be solved statistically: The word combination is also presented several users within a very short period of time and the most common input is assumed to be correct.