Terrible results from Tesseract API

[elena bresciani]

Dear all,

I need to integrate Tesseract in a C++ project.
First I simply called Tesseract from command line and, after setting up a spefic configuration I've come to satifying results.

This is the config file "pharma"

load_system_dawg 0
load_freq_dawg 0
load_punc_dawg    0
user_words_suffix pharma-words
tessedit_char_whitelist abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789,
language_model_penalty_non_dict_word 0

Now that I have to do the same thing with a Tesseract API I have terrible results, like down to 10% of correct identification and 90% garbage.
I must be missing something in the conversion to the API...

This is my code

#include <tesseract/baseapi.h>
#include <leptonica/allheaders.h>

int main(int argc, char *argv[])
{
    char *outText;
   
    tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
   
    api -> Init("/usr/local/share/","ita");
    api -> ReadConfigFile ("pharma");
   
   
    Pix *image = pixRead (argv[1]);  
    api -> SetImage (image);
    api -> SetSourceResolution(600);
   
    outText = api -> GetUTF8Text();
    printf ("OCR output: \n%s", outText);
   
    api -> End();
    delete [] outText;
    pixDestroy (&image);
   
    return 0;
  
}

Can somebody help me undestand please?
 
Thanks in advance

Elena

[Nick White]

Hi Elena,

Just a guess, but maybe this line:

> api -> SetSourceResolution(600);

is the source of your troubles? Tesseract from the command line
would have just been guessing it, and perhaps its guess, coupled
with its ideas about different sizes of fonts, were better than
yours?

Nick

[zdenko podobny]

Could you please post also testing image?

Zdenko

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[elena bresciani]

I tried to remove that line but the results are still really bad.

The problem must be somewhere else..

other suggestions? :)

Elena

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[elena bresciani]

Here's an example of the kind of text that I have to read

[zdenko podobny]

I see the problem (there may be also something else ;-) as I do not have time to test it yet):

load_system_dawg, load_freq_dawg etc. are init parameters[1] - you try it set them later they are ignored

You need to pass them to init (see section Tesseract-OCR API[2])

[1] https://code.google.com/p/tesseract-ocr/wiki/ControlParams#Init_only

[2] http://www.sk-spell.sk.cx/tesseract-ocr-parameters-in-302-version

Zdenko

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[elena bresciani]

I'm trying modify the code like you said but now I have problems with GenricVector.

I have included
<tesseract/genericvector.h>

and then wrote my code as in the example you cited

GenericVector pars_vec;
..
GenericVector pars_values;
..

But it doesn't compile and I get this error:

OCR-0.1.cpp: In function ‘int main(int, char**)’:
OCR-0.1.cpp:9:19: error: missing template arguments before ‘pars_vec’
     GenericVector pars_vec;
                   ^
OCR-0.1.cpp:9:19: error: expected ‘;’ before ‘pars_vec’
OCR-0.1.cpp:10:5: error: ‘pars_vec’ was not declared in this scope
     pars_vec.push_back("load_system_dawg");
     ^
OCR-0.1.cpp:15:19: error: missing template arguments before ‘pars_values’
     GenericVector pars_values;
                   ^
OCR-0.1.cpp:15:19: error: expected ‘;’ before ‘pars_values’
OCR-0.1.cpp:16:5: error: ‘pars_values’ was not declared in this scope
     pars_values.push_back("F");
     ^

what am I missing again?

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[zdenko podobny]

what is your version of tesseract?

what kind and version of compiler you use?

Zdenko

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[elena bresciani]

I'm using tesseract 3.02.02

 and compiling with gcc 4.8.2

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[zdenko podobny]

check this[1] - it works for me on openSUSE 13.1 64bit with tesseract 3.02.02 and gcc 4.8.1 (even the result is not the same as for command line ;-) ;

[1] http://pastebin.com/qxUPEQZm

Zdenko

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[elena bresciani]

Thank you very much!

Now for me it works exactly like from terminal.

Cheers,

Elena

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[elena bresciani]

I have one more question:

 how can I use TessResultRenderer to write output in a txt or in an hOCR file?