Sign up ×
Programmers Stack Exchange is a question and answer site for professional programmers interested in conceptual questions about software development. It's 100% free.

I don't understand why people like to say "Images had to be distorted otherwise they would be easily cracked". I'm talking about those verification images that we had to type to identify that we are humans.

Exactly what steps must we take to break even a simple image? like this: enter image description here

Ok so i'm guess we had to read all the bytes of the image and try to draw some sense out of those bytes? because if that's really how it is done it does seem really pretty tough (so what's with that comment that it's easily cracked), or is there a better way to crack images (that make it so easy after-all) ?

share|improve this question
Look into "Optical Character Recognition", Here's a wikipedia page to get you started: – FrustratedWithFormsDesigner Aug 18 '11 at 14:57

1 Answer 1

up vote 6 down vote accepted

If not distorted, using OCR it is quite easy.

By the way, there was a question on OCR yesterday (OCR - starting point) where I posted a link to Google's OCR tool. I also posted another link that may be interesting for you, in which they explain how the OCR tool treats words it cannot read,, excerpt:

"When a word in a book scan can’t be recognized by Google’s OCR software, it’s sent to the reCAPTCHA pool. So when a person enters a reCAPTCHA phrase into a form, Google can discover what its OCR program couldn’t, without having to hire human editors to review scanning results."

So: CAPTCHA --> OCR --> CAPTCHA. The circle is complete :-)

share|improve this answer
The problem with reCaptcha is that it is often obvious which of the two images is the known one - if your OCR is almost on par with reCaptcha's, you have a fairly good chance by solving the easy one and providing garbage for the other. – tdammers Aug 18 '11 at 19:08
You're right. Also, there are other problems with users with disabilities. The following article is interesting in that it shows differences between basic and advanced captchas in terms of accessibility: – Jalayn Aug 19 '11 at 5:55

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.