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Simple OCR, finding matching pattern

Posted on 2008-02-02
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Hi,
Could anybody tell me how to make simple OCR? Lets say we have B&W bitmap. It has some letters on it. Let's say that i have pattern for every letter -> b&w bitmap too ... so how do i find matches for patterns the easiest way? The problem may be that some letters may be partially out of bitmap.
Thanx for help,
FlashT
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Question by:flasht
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aikimark earned 500 total points
ID: 20805627
"how do i find matches for patterns the easiest way?"
Question: Are you trying to recognize CAPTCHA text?  That is a different problem than typical OCR.

=================
Given your beginner level status, do NOT try to program this yourself.  Use a third-party, shareware, freeware/opensource OCR library.  

Consider the following:
http://www.leadtools.com/SDK/Document/Document-Addon-ocr.htm
http://asprise.com/product/ocr/index.php?lang=c
http://www.freedownloadscenter.com/Best/ocr-delphi.html
http://www.vclcomponents.com/Delphi/Graphical_Controls/OCR_Toolkit_for_Delphi-info.html
http://www.vclcomponents.com/Delphi/Graphical_Controls/Kadmos_OCR_ICR_engine-info.html
http://www.torry.net/pages.php?id=1547
http://www.abbyy.com/
http://ccambien.free.fr/wocar/index.shtml.en
http://www.ocr.com/
http://www.screenocr.com/

Good list with some duplicates of above items:
http://www.componentsource.com/features/scanning-ocr/delphi/index.html

Article about doing this with D7 and the MS Office MODI library:
http://www.delphi3000.com/articles/article_4253.asp?SK=
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by:flasht
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I tried those but they suck badly... I do have EXACT patters for letters so the only thing I am asking is how to find matches easiest way. I'm not begginer. It's just I think there are better ways than pixel per pixel comparation...
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by:flasht
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Oh and yes I'm trying to recognize captcha... if you know any free software for that, would be useful too :)
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by:aikimark
ID: 20859627
if you have a character set and there are no morphing or obfuscating operations applied to the CAPTCHA, then I would approach the matching problem thusly:
* isolate individual CAPTCHA characters
* do your matching on a per-character basis

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Thinking of this problem as an exercise, I might be tempted to translate the characters, in both your matching set and the CAPTCHA, into vector representations and do a comparison on at the representational level.  Think TEX and LaTEX and TrueType.
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by:Computer101
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Forced accept.

Computer101
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