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Nov 13 2007

reCAPTCHA

Posted by: geoff in Clever

Here’s a really cool idea: reCAPTCHA. It’s a system which “takes scanned images from actual books, with which optical character recognition software are struggling, and uses them as the source material for CAPTCHA’s.” So when you’re proving that you’re not a robot to yet another web site (something which happens 60 million times a day, apparently), you could be helping to digitize old books.

This entry was posted on Tuesday, November 13th, 2007 at 6:38 am and is filed under Clever.You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

3 Responses to “reCAPTCHA”
  1. The Barefoot Bum says: November 14th, 2007 at 3:41 am

    I don’t get it. For a captcha image to work, we have to know ahead of time what the correct characters are, no?

  2. geoff says: November 14th, 2007 at 7:22 am

    Here’s what you’d have found if you’d clicked through to the reCAPTCHA site:

    But if a computer can’t read such a CAPTCHA, how does the system know the correct answer to the puzzle? Here’s how: Each new word that cannot be read correctly by OCR is given to a user in conjunction with another word for which the answer is already known. The user is then asked to read both words. If they solve the one for which the answer is known, the system assumes their answer is correct for the new one. The system then gives the new image to a number of other people to determine, with higher confidence, whether the original answer was correct.

    Easy, innit?

  3. The Barefoot Bum says: November 14th, 2007 at 1:25 pm

    It’s very clever.

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