Wednesday, April 11, 2012

A distinct lack of vision

Like many folks today, I'm often looking for ways to save a buck or a dime. And one perfect way to save a few pennies, of course, is to use that highly popular piece of computer software called Skype.

Now for those of you that may have been living on Mars for the past few years, Skype is a program that you can download onto your PC to enable you to engage in either voice or video conversations with other Skype users over the Interweb, saving you both vast sums of money on telephone calls - especially international ones.

For my part, I have been using Skype to discuss all things related to machine vision systems design with our European Editor, checking in with him on a regular basis to discover all the vision-related news that's coming out of hotbeds of innovation in such far flung places as Stuttgart, Germany and Cambridge, England.

But the other night, the course of the conversation turned away from vision systems and onto the subject of house renovation. You see, our European Editor has recently had his house extensively refurbished and I was keen to see what the results looked like as we chatted on his webcam.

Sadly, however, the webcam was not connected to his laptop. Rather, it had been plugged into a heavy PC tower which could not be carried around the house. But I was so keen to see the results of the work that I instructed the wretched Editor to download Skype onto his notebook and to plug the webcam into that, so that he could move around while I gazed in awe at his freshly painted rooms.

Unwilling to disobey orders, the Editor did indeed attempt to download the Skype software onto his notebook. In fact, he attempted to do so several times before finally giving up. As he tried the download time and time again with no apparent luck, his language became extremely colorful - so much so that if his comments were to be repeated here they would surely offend the sensibilities of many of our readers.

The poor European editor, it appeared, was having a great deal of problem actually registering to download the program. All because it required him to input a “Captcha” code that would enable the program to ensure that the registration screen was actually being filled out by a real human being.

This particular Captcha test required our dejected Editor to retype a series of rather warped and crowded letters that were displayed on the screen into a field below them. But the trouble was that the images were so exceptionally mangled that our Editor had little chance of recognizing any of them. Even when the system presented new Captchas after his failures, he failed to identify any of the letters.

Clearly, there's an opportunity here for anyone involved in the vision systems business to develop some vision recognition software that would enable folks like our Editor to simply point his webcam at the screen and automatically read out those codes in an accurate fashion.

Some academics at Stanford University (Stanford, CA, USA) have already taken a crack at the problem, employing machine vision algorithms to successfully crack 66 percent of Visa's Captchas, 70 percent of Blizzard's, and 25 percent of Wikipedia's. Apparently, a 1 percent successful cracking rate is regarded as grounds for the Captcha's immediate discontinuation.

Reference:Stanford Boffins on the Brink of Breaking Captcha Codes

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