[Openalpr] 如何產生測試用的車牌影像

以下介紹幾種方式，可以取得測試用的車牌影像

HLS (HTTP Live streams) 介紹

許多可以在 iPad 上正常播放的影片，並無法直接串流到 AppleTV。為了讓老婆方便看影片，因此便想找個方法讓 影片能夠串流到 AppleTV，因此需要先研究一下 HLS 機制。

[Openalpr] How to compile openalpr for Mac?

I try to compile openalpr on my MacBook Pro. Below is the note.


0. Test environment

• OS X EI Capitan (v10.11.2)
• tesseract v3.0.4
• openalpr v2.2.0
• opencv v3.0.0

1. Download source

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

2. Install Tesseract (https://code.google.com/p/tesseract-ocr/)

$ wget http://www.leptonica.com/source/leptonica-1.73.tar.gz
$ tar xvf leptonica-1.73.tar.gz
$ cd leptonica-1.73
$ ./configure CC=/usr/bin/clang
$ make
$ sudo make install 

$ cd ~/openalpr
$ git clone https://github.com/tesseract-ocr/tesseract.git tesseract-ocr
$ cd tesseract-ocr/
$ git tag -l $ git checkout tags/3.04.00
$ ./autogen.sh
$ ./configure CXX=/usr/bin/clang++ --with-extra-includes=/usr/local/include --with-extra-libraries=/usr/local/lib
$ make
$ sudo make install

3. Install OpenCV, I used OpenCV v3.0.0 that I already installed.

http://albert-oma.blogspot.tw/2015/08/how-to-install-opencv-in-mac-os.html

4. Install openalpr

$ cmake .. -DCMAKE_INSTALL_PREFIX:PATH=/usr/local -DCMAKE_INSTALL_SYSCONFDIR:PATH=/etc -DCMAKE_MACOSX_RPATH=true
$ make
$ sudo make install

5. Test

$ wget http://i.imgur.com/pjukRD0.jpg -O lp.jpg
$ alpr lp.jpg

FAQ:

1. Compile error about "undeclared identifier 'ENTER_KEY_ONE' and 'ENTER_KEY_TWO'"Referece

 https://github.com/openalpr/openalpr/blob/master/src/misc_utilities/classifychars.cpp, you will find these 2 definitions are missing for __APPLE__ platform. So you need just add below 2 lines, and it will pass the compilation.
const int ENTER_KEY_ONE = 13;
const int ENTER_KEY_TWO = 10;

2. How to generate test license plate images?

method1. download from here.
method2. use openalpr deamon to capture from a real camera or streaming server.

Reference:

1. https://github.com/openalpr/openalpr/wiki/Compilation-instructions-(OS-X)
2. http://www.vision.caltech.edu/html-files/archive.html

[Openalpr] How to cross compilation openalpr for ARM?

Recently, I survey the open source of license plate recognition. The project "openalpr" seems a good option. I reference the Compilation-instructions-(Ubuntu-Linux),  and try to run the program on arm based linux. Below is my memo.