Thursday, September 08, 2005


It stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart. Although I still wonder why it is abbreviated CAPTCHA instead of CAPTTTCHA, it was (re)brought to my attention due to the spam I got for my posting yesterday. Anyway, CAPTCHA is developed by researchers from Carnegie Mellon University. Here is their main website. Briefly, the goal of CAPTCHA project is to use Artificial Intelligence to help internet security (e.g. to prevent spams). The underlying assumption behind CAPTCHA is that there are tasks that humans can do, but computers can't. For example, since I enabled the word verification (from CAPTCHA project), each time you wish leave a comment on this blog, you will be asked to read and verify a distorted text (which is an image file). Although the task seems trivial to humans, tasks like this are non-trivial for computers (at least for now). We don't know whether computers will someday possess our ''intelligence''. But CAPTCHA is one reason why a 'no' answer will have positive impact on our society.

Ironically, the distorted texts are actually generated by computers ...


Ben said...

CAPTCHA's are pretty cool. Although computers (i.e. AI/computer vision) will get better at deciphering current CAPTCHA's, I believe that humans will keep ahead of them for some time yet.

Speaking of cool AI applications. I just learnt of this.

twidjaja said...

Ben, thanks for the reference. It's always great to see advancement like this in AI. On the other hand, I actually believe that computers will never fully outperform human beings in certain aspects. However, we'll see :-)