Wednesday, June 13, 2007

ReCaptcha

I came across this fantastic company today http://www.recaptcha.net/ via http://www.nytimes.com/2007/06/11/technology

A CAPTCHA is a program that can tell whether its user is a human or a computer. You've probably seen them — colorful images with distorted text at the bottom of Web registration forms.

reCAPTCHA improves the process of digitizing books by sending words that cannot be read by computers to the Web in the form of CAPTCHAs for humans to decipher. More specifically, each word that cannot be read correctly by OCR is placed on an image and used as a CAPTCHA. This is possible because most OCR programs alert you when a word cannot be read correctly.

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.


How cool is that - kind of like the SETI screensaver, your efforts are going to be used anyway - lets use them for good.

I think it's a fantastic project and will definitely be supporting this in the future.


Cheers,
Dean

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