Making text difficult for OCR?

[David Honig]

At 08:08 AM 8/9/01 -0000, Dr. Evil wrote:
>I have a question for you c'punks.  If you wanted to generate some
>bitmaps of text which would be difficult or impossible to OCR, but not
>too difficult for humans to read, how would you do that?  Basically, I
>want to create GIFs of text which can't be OCRed in a reliable way.
>I've thought about some things: I can put in noise pixels, I can blur
>the text, I can rotate, shear, and otherwise distort it.  Anything
>else I should do?  Will these tricks work?

Ultimately if humans can read it, a machine can, unless you believe
humans are supernatural.  However, we're frequently ignorant of how
to tell machines to perform as well as us.


If you create letters by staggering stripes, the OCR will have a hell
of a time.  

The letter I:

----__---
----__---
----__---
----__---
----__---
----__---


Also reversing the contrast (in stripes across the letter) will disrupt
simpler OCR edge tracers, though this camoflage may impair human
readability too.