INSTALL.md

In duncantl/Rtesseract: Interface to the tesseract OCR system

Tesseract 4.0 is currently not as easy to install on all systems as earlier versions. Version 4.0 is not officially released, so these difficulties are understandable.

General

• Missing eng.traineddata and other training files

The language files are specific to the Tesseract version. For Tesseract 4.0+, you can use either files from tessdata_best, as suggested here. The tessdata_fast files will also work.

For Tesseract versions 3.04+, you need to use the files from tessdata

These files can be put into the default search locations (e.g., /usr/local/share) or Tesseract can be told where to find them with the tessdata flag.

• aspell is suggested (not a dependency)

R CMD BUILD said I was missing aspell, so I got from omegahat.net You might need to apply this fix

Ubuntu

On Ubuntu, we use clang ./configure CXX=clang++ CC=clang

The option --disable-openmp doesn't disable it fully and we get an error when compiling the code in the lstm/ directory.

So we install libopenmp-dev.

On Ubuntu with clang 3.8, we added the std:: prefix in lstm/lstmrecognizer.cpp std::isnan() in LabelsViaThreshold() (See https://stackoverflow.com/questions/39130040/cmath-hides-isnan-in-math-h-in-c14-c11)

OSX

Troubleshooting

problems after install of tesseract 4.0.0-beta.4 from source

1) !strcmp(locale, "C"):Error:Assert failed

Originates with this line in baseapi.cpp: ASSERT_HOST(!strcmp(locale, C)); The error is due to a recent change in tesseract source: https://github.com/tesseract-ocr/tesseract/commit/3292484f67af8bdda23aa5e510918d0115785291#diff-903b81bdfe923135ee1d03800c400ed8 See https://github.com/tesseract-ocr/tesseract/issues/1670

Since this is an unresolved issue, for now I just undid that change in the tesseract code (in src/api/baseapi.cpp)

duncantl/Rtesseract documentation built on March 25, 2022, 5:50 a.m.