OpenALPR for Ubuntu 18.04

This is a slightly modified update to Daniel Kornev's excellent post which goes into more detail about why building from source is necessary on 18.04. His post was missing a few dependencies that I didn't have installed namely cmake, opencv and pkg-config. The following steps should get you a working build of openalpr on a fresh install of Ubuntu 18.04.

If you're not working with a fresh install, this might be a good time to clean and update your system before proceeding. (Optional)

$ sudo apt update #fetch list of available updates
$ sudo apt upgrade #install updates – does not remove packages
$ sudo apt autoremove #removes unused/outdated packages

1. Remove any previously installed versions of Tesseract & Leptonica and install all required dependencies and build tools.

# remove any tesseract binaries and languages
$ sudo apt-get remove tesseract-ocr*

# remove any previously installed leptonica
$ sudo apt-get remove libleptonica-dev

# make sure other dependencies are removed too
$ sudo apt-get autoclean
$ sudo apt-get autoremove --purge

# install libtool m4 automake cmake & pkg-config
$ sudo apt-get install libtool m4 automake cmake pkg-config

# install opencv
$ sudo apt-get install libopencv-dev

# install liblog4cplus-dev, liblog4cplus-1.1-9 and build-essential:
$ sudo apt-get install liblog4cplus-1.1-9 liblog4cplus-dev build-essential

2. Download & install leptonica 1.74.1

$ wget https://github.com/DanBloomberg/leptonica/archive/1.74.1.tar.gz

# unpack tarball and cd into leptonica directory
$ tar -xvzf 1.74.1.tar.gz
$ cd leptonica-1.74.1

# build leptonica
$ ./autobuild
$ ./configure
$ sudo make
$ sudo make install

3. Download & install tesseract 3.0.5

$wget https://github.com/tesseract-ocr/tesseract/archive/3.05.02.tar.gz

# unpack tarball and cd into tesseract directory
$ tar -xvzf
$ cd tesseract-3.05.02/

# build tesseract
$ ./autogen.sh
$ ./configure --enable-debug LDFLAGS="-L/usr/local/lib" CFLAGS="-I/usr/local/include"
$ sudo make
$ sudo make install
$ sudo make install-langs
$ sudo ldconfig

# check everything worked
$ tesseract --version

# you should see
tesseract 3.05.02
 leptonica-1.74.1

4. Install libcurl3 & update libcurl4

$ sudo add-apt-repository ppa:xapienz/curl34
$ sudo apt-get update
$ sudo apt-get install libcurl4 libcurl4-openssl-dev

5. Download and install OpenALPR

$ git clone https://github.com/openalpr/openalpr.git
$ cd openalpr/src 
$ mkdir build
$ cd build

# setup the compile environment
$ cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr -DCMAKE_INSTALL_SYSCONFDIR:PATH=/etc ..

# and compile the library
$ make && sudo make install

6. Check if everything worked! 🎉

$ wget http://plates.openalpr.com/h786poj.jpg -O lp.jpg 
$ alpr lp.jpg
# if everything worked you should see:
 plate0: 10 results
    - 786P0      confidence: 89.6593
    - 786PO      confidence: 85.9889
    - 786PQ      confidence: 85.8115
    - 786PD      confidence: 85.7408
    - 786PG      confidence: 84.4258
    - 786P       confidence: 83.0879
    - 7B6P0      confidence: 72.5012
    - 7B6PO      confidence: 68.8309
    - 7B6PQ      confidence: 68.6534
    - 7B6PD      confidence: 68.5827

Semo/OpenALPR.md