My reading of this article suggests that a benefit of ReCAPTCHA is that it can have humans verify words not recognised in the OCR/digitization of books. It does this by using these words in "Are you human?" tests. So ReCAPTCHA kills two birds with one stone. Great!

But I dont get it. If the word can't be recognised by the digitization process then what is the input entered, by the supposed human being, verified against? How does this work?

security captcha recaptcha spam-prevention
Edit
Report