Installing tesseract for python on Ubuntu 15.10

Some time ago I've already written a tutorial how to install tesseract for python on Ubuntu 14.04.
And today I've struggled with the new challenges during the installation of tesseract and python-tesseract on Ubuntu 15.10. So here is my way to make it usable.

user@server:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=15.10
DISTRIB_CODENAME=wily
DISTRIB_DESCRIPTION="Ubuntu 15.10"

Install packages
sudo apt-get install python-distutils-extra tesseract-ocr tesseract-ocr-eng libopencv-dev libtesseract-dev libleptonica-dev python-all-dev swig libcv-dev python-opencv python-numpy python-setuptools build-essential subversion git
sudo apt-get install autoconf automake libtool
sudo apt-get install libpng12-dev libjpeg62-dev libtiff4-dev zlib1g-dev

Download leptonica

wget http://www.leptonica.com/source/leptonica-1.73.tar.gz
tar xvf leptonica-1.73.tar.gz

build it

cd leptonica-1.73
./configure
make
make install

Download tesseract-ocr

wget https://github.com/tesseract-ocr/tesseract/archive/3.04.00.tar.gz

tar xvf 3.04.00.tar.gz
cd tesseract-3.04.00
./autogen.sh
./configure
make
sudo make install
sudo ldconfig

And test:

user@server:~$ tesseract
Usage:
  tesseract imagename|stdin outputbase|stdout [options...] [configfile...]

Check out `python-tesseract`

git clone https://bitbucket.org/3togo/python-tesseract.git

It's needed to update "baseapi_mini.h" file in ./python-tesseract/src/ folder:

....
class MutableIterator;
line: 85
class TessResultRenderer;
....


line 316:
  //void SetImage(const Pix* pix);
    void SetImage(Pix* pix);


line 477:
  /*
  bool ProcessPages(const char* filename,
                    const char* retry_config, int timeout_millisec,
                    STRING* text_out);
  */
  bool ProcessPages(const char* filename, 
                    const char* retry_config, int timeout_millisec, 
                    TessResultRenderer* renderer);


line 493:
  /*
  bool ProcessPage(Pix* pix, int page_index, const char* filename,
                   const char* retry_config, int timeout_millisec,
                   STRING* text_out);
  */
  bool ProcessPage(Pix* pix, int page_index, const char* filename,
                   const char* retry_config, int timeout_millisec,
                   TessResultRenderer* renderer);


It's needed to update "main.cpp" file in ./python-tesseract/src/ folder:

line: 15
#include "renderer.h"


line: 64
char* ProcessPagesWrapper(const char* image,tesseract::TessBaseAPI* api) {
const char *data = "";
tesseract::TessTextRenderer renderer(data);
api->ProcessPages(image, NULL, 0, &renderer);
return api->GetUTF8Text();
}

line: 73
char* ProcessPagesPix(const char* image,tesseract::TessBaseAPI* api) {
const char *data = "";    
tesseract::TessTextRenderer renderer(data);
int page=0;
Pix *pix;
pix = pixRead(image);
api->ProcessPage(pix, page, NULL, NULL, 0, &renderer);
free(pix->data);
free(pix->text);
return api->GetUTF8Text();
}

line: 86
char* ProcessPagesFileStream(const char* image,tesseract::TessBaseAPI* api) {
Pix *pix;
const char *data = "";
tesseract::TessTextRenderer renderer(data);
int page=0;
FILE *fp=fopen(image,"rb");
pix=pixReadStream(fp,0);
fclose(fp);
api->ProcessPage(pix, page, NULL, NULL, 0, &renderer);
free(pix->data);
free(pix->text);
return api->GetUTF8Text();
}

line 107:
char* ProcessPagesBuffer(char* buffer, int fileLen, tesseract::TessBaseAPI* api) {
FILE *stream;
stream=fmemopen((void*)buffer,fileLen,"rb");
if (stream == NULL) {
puts("cant't open stream using fmemopen");
return (char*)"Error";
}
Pix *pix;
int page=0;
const char *data = "";
tesseract::TessTextRenderer renderer(data);
pix=pixReadStream(stream,0);
if (stream != NULL)
fclose(stream);
api->ProcessPage(pix, page, NULL, NULL, 0, &renderer);
free(pix->data);
free(pix->text);
return api->GetUTF8Text();
}

and build it:

python setup.py clean
python setup.py build
sudo python setup.py install

After that try to run your python example.

If you'll get such error:
Error opening data file ./tessdata/eng.traineddata
Please make sure the TESSDATA_PREFIX environment variable is set to the parent directory of your "tessdata" directory.
Failed loading language 'eng'
Tesseract couldn't load any languages!
AdaptedTemplates != NULL:Error:Assert failed:in file adaptmatch.cpp, line 174
Segmentation fault (core dumped)

You could fix it by patching "mainblk.cpp" file inside tesseract-3.04.00/ccutil/ folder the next way:

 In the "mainblk.cpp" file code:

  if (argv0 != NULL) {
    datadir = argv0;
  } else {
    if (getenv("TESSDATA_PREFIX")) {
      datadir = getenv("TESSDATA_PREFIX");
    } else {
#ifdef TESSDATA_PREFIX
#define _STR(a) #a
#define _XSTR(a) _STR(a)
    datadir = _XSTR(TESSDATA_PREFIX);
#undef _XSTR
#undef _STR
#endif
    }
  }

  // insert code here

  // datadir may still be empty:
  if (datadir.length() == 0) {
    datadir = "./";

add into "insert code here" place the next code:

  if (getenv("TESSDATA_PREFIX")) {
      datadir = getenv("TESSDATA_PREFIX");
  } else {
    // check dir with tessdata
    struct stat sb;
    if (stat("/usr/share/tesseract-ocr/tessdata", &sb) == 0 && S_ISDIR(sb.st_mode)) {    
      datadir = "/usr/share/tesseract-ocr";
    }
  }

and include the next:

#include <sys/stat.h>

Rebuild and reinstall tesseract-ocr:

cd tesseract-3.04.00
make
sudo make install

So, after that, if you have TESSDATA_PREFIX env variable, it will be loaded, and if you have tessdata folder with files in /usr/share/tesseract-ocr/ it will be loaded, otherwise directory with your python example module (./) will be checked for tessdata folder.


Test installed python tesseract using the tests in test folder:

user@server:~/python-tesseract/src/test$ python test.py
result(ProcessPagesWrapper)= The (quick) [brown] {fox} jumps!
Over the $43,456.78 <lazy> #90 dog
& duck/goose, as 12.5% of E-mail
from aspammer@website.com is spam.
Der ,,schnelle” braune Fuchs springt
fiber den faulen Hund. Le renard brun
«rapide» saute par-dessus le chien
paresseux. La volpe marrone rapida
salta sopra i] cane pigro. El zorro
marrén répido salta sobre el perro
perezoso. A raposa marrom répida
salta sobre 0 C50 preguieoso.


result(ProcessPagesFileStream)= The (quick) [brown] {fox} jumps!
Over the $43,456.78 <lazy> #90 dog
& duck/goose, as 12.5% of E-mail
from aspammer@website.com is spam.
Der ,,schnelle” braune Fuchs springt
fiber den faulen Hund. Le renard brun
«rapide» saute par-dessus le chien
paresseux. La volpe marrone rapida
salta sopra i] cane pigro. El zorro
marrén répido salta sobre el perro
perezoso. A raposa marrom répida
salta sobre 0 C50 preguicoso.


size=156302
retStr length=422
result(ProcessPagesRaw) The (quick) [brown] {fox} jumps!
Over the $43,456.78 <lazy> #90 dog
& duck/goose, as 12.5% of E-mail
from aspammer@website.com is spam.
Der ,,schnelle” braune Fuchs springt
iiber den faulen Hund. Le renard brun
«rapide» saute par-dessus le chien
paresseux. La volpe marrone rapida
salta sopra i] cane pigro. El zorro
marrén répido salta sobre el perro
perezoso. A raposa marrom rapida
salta sobre 0 C50 preguicoso.


len=156302
result(ProcessPagesBuffer)= The (quick) [brown] {fox} jumps!
Over the $43,456.78 <lazy> #90 dog
& duck/goose, as 12.5% of E-mail
from aspammer@website.com is spam.
Der ,,schnelle” braune Fuchs springt
iiber den faulen Hund. Le renard brun
«rapide» saute par-dessus le chien
paresseux. La volpe marrone rapida
salta sopra i] cane pigro. El zorro
marrén répido salta sobre el perro
perezoso. A raposa marrom rapida
salta sobre 0 C50 preguicoso.


user@server:~/python-tesseract/src/test$ python test2.py
The (quick) [brown] {fox} jumps!
Over the $43,456.78 <lazy> #90 dog
& duck/goose, as 12.5% of E-mail
from aspammer@website.com is spam.
Der ,,schnelle” braune Fuchs springt
fiber den faulen Hund. Le renard brun
«rapide» saute par-dessus le chien
paresseux. La volpe marrone rapida
salta sopra i] cane pigro. El zorro
marrén répido salta sobre el perro
perezoso. A raposa marrom répida
salta sobre 0 C50 preguieoso.


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