At 1:01 PM -0400 5/12/06, Robert Cummings wrote:
> The original poster asked the question -- can it be done. And of
course, the answer is Yes.
Yes "it can be done". No, it's not trivial in the general.
Well... generally it's of little value to me. :-)
Visial recognition is what we are talking about when you say it's
trivial and can be done easily. Because visual recognition is the
necessary branch of analysis required to be able to analyse any captcha
and come up with the answer.
I say it's trivial because it's not important. I also say it's
trivial because what I have seen and worked on makes it pale in
comparison.
Granted, the more complex the image, the more difficult for a program
to decipher it, but a CAPTCHA has to be, by definition, detectable by
a visually unimpaired human.
And you're making what point here? That you can write code to match the
capabilities of a visually unimpaired human's visual processing and
recognition? Wow!!
No the point I am making here is that CAPTCHA is used weed out bots
from persons who ARE NOT visually impaired -- and thus, the objection
to it's use because CAPTCHA is a device that goes against the ADA and
all those who care about access for persons with visual disabilities.
As for visual processing, we do have screen readers -- they do work.
You say otherwise?
Could I write that software? Yes I could. I even wrote a Macintosh
blind browser that would capture the content of a web page and read
it aloud -- however -- that was not image recognition, but rather
text to speech processing. Have I written tools to analyze signals
and detect anomalies? Yes. Have I written AI programs? Yes. But,
what's the point here? It isn't IF I could do it, but rather IF it
can be done -- and it HAS been done.
The only issue you are arguing here is IF it is trivial or not. I say
it's trivial and you say otherwise. Okay, you're entitled to your
opinion -- as am I. Everyone has the right to be wrong. :-)
> Image analysis, enhancement, alteration, and such are better
performed by computers than by humans -- that's the reason we
developed the software in the first place.
WRONG! A small subset of these are better performed by computers.
Bull--toot!
You say that you're better than PhotoShop at doing frequency
analysis, bright/contrast, color levels and such -- now that's funny.
I know you didn't actually mean that.
And in
almost every case, the computer's results are checked by humans
afterwards. Most computers just flag things as interesting, then a human
goes and makes the executive decision.
As it should be -- BUT -- the computer is still making a decision to
show something, is it not? It's still a conditional outcome, right?
It flags stuff for a reason.
> The step between analysis and detection is simply meeting an
acceptable error threshold.
Maybe so, and I guess if you considering .00000001 success rate ok, then
writing a captcha breaker might be trivial since you can probably just
generate a random string.
It's all relative, isn't it? Like my success rate at winning an
argument with my wife, that figure you gave above would be pretty
high for that. :-)
> As for me being naive -- well... either one of us could be -- but
that's probably what I get for working in signal analysis (seismic
data) since 1975.
Someone once posted the following to the list, I feel it appropriate to
quote it at this time:
"Locus ab auctoritate est infirmissimus"
LOL -- You got me on that one! I almost posted that quote as a
framework for me using my "authoritative argument". I hate it when my
words come back to bite me in the butt.
But, in my defense, 31 years of working with signals (granted, it
long enough ago that the first ones were smoke), has given me a
perspective that everything can be distilled down to components and
those components can be analyzed.
And from that analysis, one can make a more informed "final"
decision. However, you must also realize that the computer (via the
programmer) has helped you arrive at the final decision -- and that
took countless smaller decisions. It's not that much different than
programming.
I gave a talk one time for the AAPG regarding AI in the Geosciences
and someone asked me to provide an example of a computer being
smarter than me. I answered that many times I have been able to
research and write a routine that would record what I learned about a
specific algorithm at that point in my life (my apex of knowledge for
that subject).
After writing the routine, I could then dummy-up and go on about my
life researching other routines in similar fashion. However, my
routines would retain the apex of my knowledge about a specific topic
and if I placed two of these routines in concert to generate an
outcome, then the outcome would surpass what I could have done. In
that fashion, my computer generated intelligence surpassing my own.
Granted, some say that a computer unplugged would still do that.
> As for the bleeding edge, that's obvious, just look to medical
imaging. They wish that the detection of their problems were as
> simple as CAPTCHA.
Just because they may wish they were detecting something simpler such as
captcha (maybe, since I could render my captcha to look like medical
imagery and so it would be just as difficult to detect), doesn't mean
captcha is trivial. I'm not currently aware of too much medical imaging
processing that occurs without human intervention. Much of it requires
that a human view the results and make an informed decision based on the
computers analysis. I think part of your naivety is thinking that the
captcha you see right now is as hard as it gets. You are very mistaken.
Mistaken? I've been there before -- and will be again. But, you still
haven't persuaded me that deciphering a CAPTCHA ranks in any fashion
whatsoever to the problems that computers are currently solving. It's
still a trivial problem.
Thanks for the exchange.
tedd
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