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Old 08-19-2008, 06:46 PM
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DaveSawers DaveSawers is offline
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Default Re: Finally CAPTCHAs Are Useful?

Quote:
Originally Posted by deepsand View Post
If OCR has not already been able to digitize the words, then how can the respondent's entry be validated? Answer - it can't. And, if it could, then the pretense of ones "helping" to transcribe old books falls apart.

TicketMaster switched to such. All one need do is to "guess" closely enough.
And the answer (quoting from the site) is:

"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."
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Last edited by DaveSawers; 08-19-2008 at 06:52 PM. Reason: clarity
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