So what is CAPTCHA? CAPTCHA is derived from the word "capture" but also is a contrived acronym of "Completely Automated Public Turing test to tell Computer and Humans Apart" .This is normally used to differentiate between human users from software programs (robots) in today's web based systems like Emails,Forums,Wiki's,Blogs etc.The main objective is to prevent software robots spamming these respective web based systems with mal content.So when we try to register with a website or post comment in a blog we are asked to enter a series of characters (usually mix of alphabets and number) displayed in a distorted fashion.This distortion and noise is added to ensure that only human intelligence can properly read and understand it.
This text based scheme has two issues - a) language dependence and data entry.This needs to be culture aware for human users to understand it properly and then data needs to manually keyed into the system.Google has recently released a research paper which overcomes these problems of text based recognition.This CAPTCHA technique is based upon identification of upright orientation of images.
The major challenge involved in this task is to remove the set of images that
- Are easy for automated orientation detection systems to identify
- Hard for human beings to identify proper orientation
To know about how it is done checkout the paper:
http://www.richgossweiler.com/projects/rotcaptcha/rotcaptcha.pdf
Let's see when we will find this in the web pages we use as netizens.
This seems to be big step for the fight against SPAM.
