Google recently bought reCaptcha, a company whose program helps foil bots. You have probably seen such anti-spam services where you have to decode distorted phrases or words to join the website or access certain pages. The interesting thing is that reCaptcha uses their service to help the digitization of books. When a digitization project has words that their OCR programs cannot decode, they can use reCaptcha to have computer users solve it. As their website says:
- "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.