Introduction: defects caused by printing and scanning



Introduction: –

Captcha is an automated security which is used to decide whether the web page is being used by the humans are the robots. It is a technology which present robots cannot pass through and is completely of puzzles, problems and pictures which humans can easily understand and pass through to it. The problems which are highly unsolvable to sort out are made easy for the highly successful for captcha which is designed to solve artificial intelligence problems Humans introduce a robotic test which present computers pass through and humans can easily have access through it. The problems which are highly unsolvable can be solved using captcha which have high success on artificial intelligence.

Captcha is used to decide whether you are human are not

Provides a puzzle which is difficult for computer and easy for humans

If the puzzle is solved you are considered as human, if not it is considered as robot

It is available in form of: –    

Captcha which is in printed form is difficult to break

Lots of algorithms are present in market to generate this kind of captcha

This are very easy for humans to identify

There are two major types of text they are Baggle text, pessimal print

Baffle text uses pronounceable English characters which are not present in English dictionary

Pessimal text uses the degradation model simulating phusical defects caused by printing and scanning of printed text

Handwritten chaptcha

Uses of transformations by adding lines, arcs, circles etc.

Uses of captcha

Online polls

Free email services

Search engine bots

Prevention to worms and spams

Preventing dictionary attack etc.


Captcha should be automatically generated and graded

Test can be taken quickly and easily by human users

Test will accept virtually all humans users and reject software agents

Test will resist automatic attack for many years despite thee technology advances and prior knowledge of algorithms


Final thoughts

Hopefuly, they will becoe more user-friendly to people with disabilities (visual, mental)

Captchas are mainly produced form AJAX and PHP technology

Various algorithms are present


Conclusion: –



I'm Mary!

Would you like to get a custom essay? How about receiving a customized one?

Check it out