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Empty requests despite Captcha

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gm.tc View Drop Down
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    Posted: 18 June 2013 at 9:32am
Hello,
 
I installed the Web Wiz Captcha a few weeks ago. But in the last time there are coming empty requests again and again.
 
This is the code for the configuration of the colors and lines:
 
'Background Colour
strCanvasColour = "ffffff"
'Border Colour
strBorderColour = "B79A5C"
'Character Colour
strCharacterColour = "B79A5C"

'Random Character Line Placement
'This places the characters at different line levels on the canvas, this is good at preventing OCR software reading the image but still allows the image to be readable for humans
blnRandomLinePlacement = True

'Random Character Skewing
'Random Skewing is good at preventing OCR software recognising characters
blnSkewing = True

'Making one of the noise levels and line noise the same as the background colour and the other the same as the character colour
'is good at preventing OCR software recognised characters by using colour filters to remove noise
'Pixelation Noise #1
'This is the pixelation noise level, random pixels which prevent OCR software recognising characters
intNoiseLevel1 = 6
strNoiseColour1 = "ffffff"
'Pixelation Noise #2
intNoiseLevel2 = 6
strNoiseColour2 = "000000"

'Noise Lines #1
'Random lines overlaying image, prevents OCR software recognising characters, but can quickly make the image difficult for a human to read
intNoiseLines1 = 8
strNoiseLinesColour1 = "000000"
'Noise Lines #2
intNoiseLines2 = 8
strNoiseLinesColour2 = "ffffff"
 
Captcha looks like this:
http:// - http://s1.directupload.net/images/130618/s47ys45k.png

 
Design is based on the design of the website. Colors should definately not be replaced.
I think the level of difficulty is strong enough, when I make it more difficult maybe the users can't read it anymore. Has somebody a solution for this problem?
 
Thank you very much,
kind regards


Edited by WebWiz-Bruce - 18 June 2013 at 10:48am
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Post Options Post Options   Thanks (1) Thanks(1)   Quote WebWiz-Bruce Quote  Post ReplyReply Direct Link To This Post Posted: 18 June 2013 at 10:40am
The colours that you use would be very easy for OCR software to read the code. As your character code is a different colour to the noise colours all the OCR software needs to do is look at the character colour "B79A5C" and it immediately filters the noise making it simple for the OCR software to read.

Change all the black noise colours "000000" to the brown character colour "B79A5C" to make it harder for any OCR software to filter the noise from the image.

Remember you need to make it hard for a computer to read, not a human. Computers can easily filter an image by removing colours, even slight shades that a human could not see the difference in. Humans are much better at grouping blocks of colours together to see a pattern emerge like a character.


Edited by WebWiz-Bruce - 18 June 2013 at 10:47am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gm.tc Quote  Post ReplyReply Direct Link To This Post Posted: 18 June 2013 at 10:55am

Thank you WebWiz-Bruce for your answer.

I will change the colours so that the character colour and the other colours are the same.

I didn't knew that the OCR-Software only has to filter the other colour.
Now of course it all makes sense.
 
I hope the OCR-Software has no success in future Big smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gm.tc Quote  Post ReplyReply Direct Link To This Post Posted: 05 July 2013 at 10:24am
Hi,
 
unfortunately there was a new empty form incoming.
Now the captcha looks like this:
 
s1.directupload.net/images/130705/7icj47iq.jpg 
 
I only changed the black colour to brown.
 
Should I increase the lines & points?
Sorry for frequently asking, but I dont know how to make it right.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WebWiz-Bruce Quote  Post ReplyReply Direct Link To This Post Posted: 05 July 2013 at 1:51pm
Maybe try the new version which adds more colours and noise to the image.

Unfortunately the OCR software used by spammers to read CAPTCHA code is getting better and better all the time at reading CAPTCHA codes.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gm.tc Quote  Post ReplyReply Direct Link To This Post Posted: 05 July 2013 at 2:14pm
Yes I know, OCR Software is getting better and better.
I will add more colours and noise, I hope it will help.
 
Thank you very much for your answer!
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