How to build latest tesseract & Leptonica from source on Ubuntu 16.04

By 三好Daddy - March 21, 2017

Refers:

https://github.com/tesseract-ocr/tesseract/wiki/Compiling

http://www.leptonica.org/

Install dependencies if needes:

sudo apt-get install autoconf automake libtool
sudo apt-get install autoconf-archive
sudo apt-get install pkg-config
sudo apt-get install libpng12-dev
sudo apt-get install libjpeg8-dev
sudo apt-get install libtiff5-dev
sudo apt-get install zlib1g-dev

 
if you plan to install the training tools, you also need the following libraries:

sudo apt-get install libicu-dev
sudo apt-get install libpango1.0-dev
sudo apt-get install libcairo2-dev

build Leptonica from source.
Click here to download the source

The README gives an overview of installation and usage

gunzip leptonica-1.74.1.tar.gz
tar -xvf leptonica-1.74.1.tar

./configure

make

sudo make install
build Tesseract from source:
git clone --depth 1 https://github.com/tesseract-ocr/tesseract.git
cd tesseract
./autogen.sh
./configure --enable-debug
LDFLAGS="-L/usr/local/lib" CFLAGS="-I/usr/local/include" make
sudo make install
sudo ldconfig
 
build training tools if you like: 
make training
sudo make training-install 

Run tesseract:
tesseract imagename outputbase [-l lang] [--psm pagesegmode] [configfiles...]

tesseract 
Usage:
  tesseract --help | --help-psm | --help-oem | --version
  tesseract --list-langs [--tessdata-dir PATH]
  tesseract --print-parameters [options...] [configfile...]
  tesseract imagename|stdin outputbase|stdout [options...] [configfile...]

OCR options:
  --tessdata-dir PATH   Specify the location of tessdata path.
  --user-words PATH     Specify the location of user words file.
  --user-patterns PATH  Specify the location of user patterns file.
  -l LANG[+LANG]        Specify language(s) used for OCR.
  -c VAR=VALUE          Set value for config variables.
                        Multiple -c arguments are allowed.
  --psm NUM             Specify page segmentation mode.
  --oem NUM             Specify OCR Engine mode.
NOTE: These options must occur before any configfile.

Page segmentation modes:
  0    Orientation and script detection (OSD) only.
  1    Automatic page segmentation with OSD.
  2    Automatic page segmentation, but no OSD, or OCR.
  3    Fully automatic page segmentation, but no OSD. (Default)
  4    Assume a single column of text of variable sizes.
  5    Assume a single uniform block of vertically aligned text.
  6    Assume a single uniform block of text.
  7    Treat the image as a single text line.
  8    Treat the image as a single word.
  9    Treat the image as a single word in a circle.
 10    Treat the image as a single character.
 11    Sparse text. Find as much text as possible in no particular order.
 12    Sparse text with OSD.
 13    Raw line. Treat the image as a single text line,
   bypassing hacks that are Tesseract-specific.
OCR Engine modes:
  0    Original Tesseract only.
  1    Neural nets LSTM only.
  2    Tesseract + LSTM.
  3    Default, based on what is available.

Single options:
  -h, --help            Show this help message.
  --help-psm            Show page segmentation modes.
  --help-oem            Show OCR Engine modes.
  -v, --version         Show version information.
  --list-langs          List available languages for tesseract engine.
  --print-parameters    Print tesseract parameters to stdout.