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130 lines
3.9 KiB
Markdown
130 lines
3.9 KiB
Markdown
openalpr
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========
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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.
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Check out a live online demo here: http://www.openalpr.com/demo.html
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User Guide
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-----------
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OpenALPR includes a command line utility. Simply typing "alpr [image file path]" is enough to get started recognizing license plate images.
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For example, the following output is created by analyzing this image:
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The library is told that this is a Missouri (MO) license plate which validates the plate letters against a regional template.
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```
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user@linux:~/openalpr$ alpr ./samplecar.png -t mo -r ~/openalpr/runtime_dir/
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plate0: top 10 results -- Processing Time = 58.1879ms.
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- PE3R2X confidence: 88.9371 template_match: 1
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- PE32X confidence: 78.1385 template_match: 0
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- PE3R2 confidence: 77.5444 template_match: 0
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- PE3R2Y confidence: 76.1448 template_match: 1
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- P63R2X confidence: 72.9016 template_match: 0
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- FE3R2X confidence: 72.1147 template_match: 1
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- PE32 confidence: 66.7458 template_match: 0
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- PE32Y confidence: 65.3462 template_match: 0
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- P632X confidence: 62.1031 template_match: 0
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- P63R2 confidence: 61.5089 template_match: 0
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```
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Detailed command line usage:
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```
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user@linux:~/openalpr$ alpr --help
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USAGE:
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alpr [-t <region code>] [-r <runtime_dir>] [-n <topN>]
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[--seek <integer_ms>] [-c <country_code>]
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[--clock] [-d] [-j] [--] [--version] [-h]
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<image_file_path>
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Where:
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-t <region code>, --template_region <region code>
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Attempt to match the plate number against a region template (e.g., md
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for Maryland, ca for California)
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-r <runtime_dir>, --runtime_dir <runtime_dir>
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Path to the OpenAlpr runtime data directory
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-n <topN>, --topn <topN>
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Max number of possible plate numbers to return. Default=10
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--seek <integer_ms>
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Seek to the specied millisecond in a video file. Default=0
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-c <country_code>, --country <country_code>
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Country code to identify (either us for USA or eu for Europe).
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Default=us
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--clock
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Measure/print the total time to process image and all plates.
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Default=off
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-d, --detect_region
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Attempt to detect the region of the plate image. Default=off
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-j, --json
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Output recognition results in JSON format. Default=off
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--, --ignore_rest
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Ignores the rest of the labeled arguments following this flag.
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--version
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Displays version information and exits.
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-h, --help
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Displays usage information and exits.
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<image_file_path>
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(required) Image containing license plates
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OpenAlpr Command Line Utility
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```
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Compiling
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-----------
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OpenALPR compiles and runs on Linux, Mac OSX and Windows.
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OpenALPR requires the following additional libraries:
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- Tesseract OCR v3.x (https://code.google.com/p/tesseract-ocr/)
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- OpenCV v2.4.x (http://opencv.org/)
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After cloning this GitHub repository, you should download and extract Tesseract and OpenCV source code into their own directories. Compile both libraries.
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Update the src/CMakeLists.txt file in the OpenALPR project. Update the following lines to match the directories of your libraries on your system:
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- SET(OpenCV_DIR "../libraries/opencv/")
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- SET(Tesseract_DIR "/home/mhill/projects/alpr/libraries/tesseract-ocr")
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Finally, in the src directory, execute the following commands:
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- cmake ./
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- make
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If all went well, there should be an executable named *alpr* along with *libopenalpr.a* that can be linked into your project.
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Questions
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---------
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Please post questions or comments to the Google group list: https://groups.google.com/forum/#!forum/openalpr
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License
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-------
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Affero GPLv3
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http://www.gnu.org/licenses/agpl-3.0.html
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