On Tuesday 20 September 2005 1:28 pm, Steven Lumos wrote:

> OCR isn't *that* easy. Humans--even young children--far exceed
> machines in discerning even relatively clean machine-print characters.

If your eyesight is normal.  There are LOTS of people who do not have normal 
eyesight.

<anecdote>
My wife holds a driver's license (and drives), is an EMT, and can pretty much 
do anything anyone else does, but captchas are difficult for her because of 
her eyesight.  If a normal set of eyes are likened to monitor resultions, and 
are said to be 1280x1024, her eyes are like an 800x600 or 640x480 monitor.  
It's still crisp and clear, but the resolution is lower.  That alone makes 
many styles of captcha difficult for her.
</anecdote>

For a large chunk of the population, captchas are quick and easy and fine, but 
for a small but not insignificant chunk, they are difficult to impossible.  
And even if a machine can only handle 10% of captchas, that is a high enough 
percentage to render them ineffective, IMHO.


Kirk Haines