openalpr
========

OpenALPR is an open source *Automated License Plate Recognition* library written in C++.  The library analyzes images and identifies license plates.  The output is the text representation of any license plate characters found in the image.

Check out a live online demo here: http://www.openalpr.com/demo.html

User Guide
-----------


OpenALPR includes a command line utility.  Simply typing "alpr [image file path]" is enough to get started recognizing license plate images.

For example, the following output is created by analyzing this image: 
![Plate Image](http://www.openalpr.com/images/demoscreenshots/plate3.png "Input image")


The library is told that this is a Missouri (MO) license plate which validates the plate letters against a regional template.

```
user@linux:~/openalpr$ alpr ./samplecar.png -t mo -r ~/openalpr/runtime_dir/

plate0: top 10 results -- Processing Time = 58.1879ms.
    - PE3R2X     confidence: 88.9371	 template_match: 1
    - PE32X      confidence: 78.1385	 template_match: 0
    - PE3R2      confidence: 77.5444	 template_match: 0
    - PE3R2Y     confidence: 76.1448	 template_match: 1
    - P63R2X     confidence: 72.9016	 template_match: 0
    - FE3R2X     confidence: 72.1147	 template_match: 1
    - PE32       confidence: 66.7458	 template_match: 0
    - PE32Y      confidence: 65.3462	 template_match: 0
    - P632X      confidence: 62.1031	 template_match: 0
    - P63R2      confidence: 61.5089	 template_match: 0

```

Detailed command line usage:

```
user@linux:~/openalpr$ alpr --help

USAGE: 

   alpr  [-t <region code>] [-r <runtime_dir>] [-n <topN>]
         [--seek <integer_ms>] [-c <country_code>]
         [--clock] [-d] [-j] [--] [--version] [-h]
         <image_file_path>


Where: 

   -t <region code>,  --template_region <region code>
     Attempt to match the plate number against a region template (e.g., md
     for Maryland, ca for California)

   -r <runtime_dir>,  --runtime_dir <runtime_dir>
     Path to the OpenAlpr runtime data directory

   -n <topN>,  --topn <topN>
     Max number of possible plate numbers to return.  Default=10

   --seek <integer_ms>
     Seek to the specied millisecond in a video file. Default=0

   -c <country_code>,  --country <country_code>
     Country code to identify (either us for USA or eu for Europe). 
     Default=us

   --clock
     Measure/print the total time to process image and all plates. 
     Default=off

   -d,  --detect_region
     Attempt to detect the region of the plate image.  Default=off

   -j,  --json
     Output recognition results in JSON format.  Default=off

   --,  --ignore_rest
     Ignores the rest of the labeled arguments following this flag.

   --version
     Displays version information and exits.

   -h,  --help
     Displays usage information and exits.

   <image_file_path>
     (required)  Image containing license plates


   OpenAlpr Command Line Utility
```


Compiling
-----------

OpenALPR compiles and runs on Linux, Mac OSX and Windows.

OpenALPR requires the following additional libraries:

    - Tesseract OCR v3.x (https://code.google.com/p/tesseract-ocr/) 
    - OpenCV v2.4.x (http://opencv.org/)

After cloning this GitHub repository, you should download and extract Tesseract and OpenCV source code into their own directories.  Compile both libraries.

Update the src/CMakeLists.txt file in the OpenALPR project.  Update the following lines to match the directories of your libraries on your system:

    - SET(OpenCV_DIR "../libraries/opencv/")
    - SET(Tesseract_DIR "/home/mhill/projects/alpr/libraries/tesseract-ocr")

Finally, in the src directory, execute the following commands:

    - cmake ./
    - make

If all went well, there should be an executable named *alpr* along with *libopenalpr.a* that can be linked into your project.


Questions
---------
Please post questions or comments to the Google group list: https://groups.google.com/forum/#!forum/openalpr

License
-------

Affero GPLv3
http://www.gnu.org/licenses/agpl-3.0.html