I’ve had much feedback in the past regarding my CAPTCHA code, MT-SCode. IT was either completely ineffectual for computerized spammers to break, or it was impossible for real people to read. Also, if your temp directory for the plugin was set to /var/tmp, the contents of the folder would get periodically cleaned up, removing all of the images for the SCode to function. Meh, the latter problem was mostly my fault.
So, out with the old, and in with the new. I’ve switched over to reCAPTCHA, an online free service provided by Carnegie Mellon University that not only provides good visual *and* audio CAPTCHA, it also helps in the digitizing of books (by providing OCR-unreadable words in the code, of all things).
About 60 million CAPTCHAs are solved by humans around the world every day. In each case, roughly ten seconds of human time are being spent. Individually, that’s not a lot of time, but in aggregate these little puzzles consume more than 150,000 hours of work each day. What if we could make positive use of this human effort? reCAPTCHA does exactly that by channeling the effort spent solving CAPTCHAs online into “reading” books.
To archive human knowledge and to make information more accessible to the world, multiple projects are currently digitizing physical books that were written before the computer age. The book pages are being photographically scanned, and then, to make them searchable, transformed into text using “Optical Character Recognition” (OCR). The transformation into text is useful because scanning a book produces images, which are difficult to store on small devices, expensive to download, and cannot be searched. The problem is that OCR is not perfect.
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.
It’s pretty awesome if you ask me, and some smart person rigged it up to work with Movable Type, so I thought, “Hey, I use Movable Type, and I’m also looking for some proper kind of CAPTCHA code for my comments.” Everyone’s happy. Or are they?
Try leaving me a comment and see if the new system’s working for you. I personally found the audio code difficult to understand — like hitting one of those CIA beacons with your shortwave, and possibly six other radio stations at the same time.