Too few characters. Skipping this page

[Chris Nevin]

Hello,

 I am having some trouble getting Tesseract to recognize individual characters. Whenever I think I have overcome actual errors, I get the line "Too few characters. Skipping this page"

Because I am using Tess4J I have been struggling to find out exactly what all of the different options you can set for Tesseract actually are. Would anyone be able to tell me if there is a way to set it to not limit the minimum number of characters on a page?

Also, I am trying to get Tesseract to recognise characters from chemical elements (example attached.) Will Tesseract be able to ignore the structure and just pick up on the characters?

Basically any advice as to what would be a good way to go about this would be helpful! Even if I should look at training Tesseract or creating a word list with the chemical elements or something?

Thanks a lot!

   Chris

[Hakan Usakli]

In case it helps someone,

Yes there is a way to change the behaviour of 'minimum number of characters' I struggled with the same problem you have as well for a while

In this file,

https://github.com/tesseract-ocr/tesseract/blob/master/ccmain/osdetect.cpp

change the value of this constant to something like 5. Recompile and you are done.

const int kMinCharactersToTry = 50

I have asked the developers to make a command line setting of that internal constant. If/When they do it I dont know.

Enjoy

Hakan

[Zdenko Podobný]

If you need to detect just orientation it should be faster to use only leptonica functions. See

https://tpgit.github.io/Leptonica/flipdetect_8c_source.html

http://tpgit.github.io/Leptonica/skew_8c_source.html

Zdenko

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[Hakan Usakli]

Hello Zdenko,

Thank you for that tip.

Yes I am extremely interested in using Leptonica functions directly, especially if they are expected to run faster.

But I am almost illiterate on C - I have the precompiled Leptonica DLL's

they are called

liblept-5.dll (7969kb)

or

pvt.cppan.demo.danbloomberg.leptonica-1.74.4.dll (1681kb)

I tried finding the function entry points with InterOpSignatureToolkit, that can make a .NET wrapper signature but It fails to load those DLL's, saying there is no assembly manifest.

How can I use Leptonica from the command line or call the DLL's from .Net ?

Any tips much appreciated

Hakan

http://tpgit.github.io/Leptonica/skew_8c_source.html

Zdenko

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