

Gmail fights image spam with OCR - brlewis
http://www.google.com/mail/help/fightspam/spamexplained.html

======
ivankirigin
That's pretty cool.

But there could be a reverse CAPTCHA where spammers send images with text that
OCR engines can't recognize.

Any public breakthrough in OCR to solve the spam-CAPTCHA would actually hurt
efforts to stop spammers who could beat CAPTCHAs to signup for more accounts.
How ironic :)

~~~
codeslinger
Spammers have employed this technique since roughly about the time they
started sending images. See here for some examples:

<http://www.jgc.org/tsc.html>

Also, real OCR is too expensive to do at the volumes of mail being sent today.
Gmail is likely using an OCR-esque technique that has lower precision but is
much faster to process a given image.

------
Tichy
I don't suppose they use tesseract, though? I tried it recently, and it didn't
recognize anything. Admittedly my test was not very thorough.

