Add automatic captcha verification

[mhutter]

Add automatic captcha verification so one can use this tool in automated jobs etc.

Possible 3rd-party tools: Tesseract-OCR

(Yes, I thought about contributing (provided I can spare some time) but I'm a Python-noob ;-) )

[petermanser]

Good point, and yes we discussed about that. We try to find a solution, but it's not that easy. :)

[dbrgn]

I messed around a lot with Tesseract, but could not reach a 33% success ratio. Maybe I did something wrong. But I think the current solution is quite ok. But if someone wants to do captcha recognition - go on :)

And you can learn Python very quickly, especially in case you know Ruby :)

[dbrgn]

Das sieht recht interessant aus. In Kombination mit etwas Bildbearbeitung könnte man das Captcha ev. knacken. http://code.google.com/p/pytesser/

[mhutter]

The Idea, as far as I understood it:

1. Convert the Image to a "simple", monochrome format to increase "readability" for OCR-Software (ie. with ImageMagick, or whatever tools are common in python)
2. OCR-Magicz, win!

BTW: Startet dabbling in an Python-Tut today... looks pretty easy/cool!

[dbrgn]

mhutter, exactly, that's what i did with commandline tools (imagemagick and tesseract). and i never really succeeded.

i'll probably try again next week with pytesser. might work.

what also could help is a training file for tesseract. but i never really understood how to make those, because i never invested enough time in it. could also help to solve the problem.

[luxflux]

what about asciiart? so at least its not another window (not that cool with a tiling wm like aweseome).

[mhutter]

luxflux, not an option if you want to send messages automatically ;-)

[dbrgn]

mhutter, if you want reliable auto-sent messages, e.g. server warnings, you should not rely on xtrazone and use a sms service instead.

luxflux, i tried it, it only works if the window is large enough. maybe we could make it an option, but shouldn't be the default imo.

[mhutter]

gwrtheyrn I agree, but it would be a nice feature ;-)

[luxflux]

gwrtheyrn, why does it need a big window? i mean how big is your console window? i use 139x42 for pyxtra...

or make it optional?

[petermanser]

luxflux: 1 char != 1 pixel.. you need to scale in order to make the ascii captcha readable :)

[luxflux]

petermanser: this was colums x lines, not pixels :) or the other way around :D

[dbrgn]

luxflux: this is a pretty large ascii-captcha, easily readable:

http://imgur.com/Y96UN

and this is the same captcha at a smaller size:

http://imgur.com/AOIVe

as you can see, as the screen/window size gets smaller, it's not readable anymore. especially if the captcha image is larger than the one i used as an example.

[boardend]

char[][] ?

http://i.imgur.com/7N5rC.png

good n8 :)

[dbrgn]

@boardend: hm?

[boardend]

If you can put the Asciiart „Image“ into a multid. char-array, it should be easy to find the columns, which are empty (filled with #). So you can separate the chars and let the user solve ony by one. This solves the problem with the width of the shell.

Was just an idea, but could be a workaround, if the creation of the captcha-window fails?!

But finally, OCR ftw :-)

[mhutter]

Hm but keep in mind that sometimes letters in the Captcha-Image may be overlapping...

[dbrgn]

Ah, sounds like an interesting idea. But then it would be better to separate the letters before the ASCII-conversion.

I think either we should show the entire CAPTCHA as ASCII and simply require a sufficiently big resolution, or not do it at all.

But we'll give OCR another try next week.

Btw, http://en.wikipedia.org/wiki/Connected_component_labeling

[dbrgn]

@mhutter: They only overlap in about 5-10% of the cases. That's bearable. I think everything over a 33% success ratio is OK.

[boardend]

I think, the user should see when there are two chars at one?

[petermanser]

I'm not sure if it's not better to spend this effort into automatic reading of the captcha. :)

[petermanser]

automatically cracking captcha \o/, rewritten the login mechanism (closed by 5937edbcd9f265521810799256752f08ae3493fb)

[luxflux]

works for me, thx!

[petermanser]

awesome :)