Ubuntu16.04安装opencv3.4.1

1. 去官网下载opencv，在本教程中选用的时opencv3.4.1，其他版本的配置方法异曲同工。 
   下载链接http://opencv.org/releases.html，选择sources版本
2. 解压下载下来的zip包
   
3. 进入到解压后的文件包中
   
4. 安装依赖库和cmake ，如果提醒需要apt-get update，那就先sudo su进入root权限，再sudo apt-get update，然后在执行下面命令

sudo apt-get install cmake 

sudo apt-get install build-essential libgtk2.0-dev libavcodec-dev libavformat-dev libjpeg.dev libtiff4.dev libswscale-dev libjasper-dev     

       5.安装完cmake之后执行命令 ,创建编译文件夹，不创建的会提示In-source builds are not allowed.

mkdir my_build_dir
cd my_build_dir

        6.cmake一下

cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..

        7.执行命令，漫长的编译过程

期间可能会出现一些ERROR; 下面是我遇上的及解决办法.

首先如果以前有装了ffmpeg,先到ffmpeg的目录下uninstall,否则opencv安装会有冲突

• 错误一

moc: Cannot open options file specified with @
Usage: moc [options] 
  -o           write output to file rather than stdout
  -I            add dir to the include path for header files
  -E                 preprocess only; do not generate meta object code
  -D[=]  define macro, with optional definition
  -U          undefine macro
  -i                 do not generate an #include statement
  -p           path prefix for included file
  -f[]         force #include, optional file name
  -nn                do not display notes
  -nw                do not display warnings
  @            read additional options from file
  -v                 display version of moc
make[2]: *** [modules/highgui/src/moc_window_QT.cxx] Error 1
make[1]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/all] Error 2
make: *** [all] Error 2

解决办法: If there is an accented character in the path name to the source files you may get this error. Move the source directory to a directory so that there is no accented characters in the path name. Then restart the compilation.

因为我放在了有中文的路径下,后来挪到没中文的路径下就不会报这个错误了;

• 错误二

Traceback (most recent call last):
  File "/media/stefan/A050780B5077E706/_raspi/opencv/sources/modules/java/generator/gen_java.py", line 1559, in 
    generator.gen(srcfiles, module, dstdir)
  File "/media/stefan/A050780B5077E706/_raspi/opencv/sources/modules/java/generator/gen_java.py", line 1061, in gen
    self.gen_class(ci)
  File "/media/stefan/A050780B5077E706/_raspi/opencv/sources/modules/java/generator/gen_java.py", line 1460, in gen_class
    for fi in ci.getAllMethods():
  File "/media/stefan/A050780B5077E706/_raspi/opencv/sources/modules/java/generator/gen_java.py", line 824, in getAllMethods
    result.extend([fi for fi in sorted(self.methods) if fi.isconstructor])
TypeError: unorderable types: FuncInfo() < FuncInfo()
modules/java/CMakeFiles/opencv_java.dir/build.make:86: recipe for target 'modules/java/photo+CalibrateCRF.java' failed
make[2]: *** [modules/java/photo+CalibrateCRF.java] Error 1
CMakeFiles/Makefile2:6282: recipe for target 'modules/java/CMakeFiles/opencv_java.dir/all' failed
make[1]: *** [modules/java/CMakeFiles/opencv_java.dir/all] Error 2
Makefile:137: recipe for target 'all' failed
make: *** [all] Error 2

解决办法:

cmake -D CMAKE_BUILD_TYPE=RELEASE -D WITH_QT=ON -D WITH_OPENGL=ON -D WITH_TBB=ON -D CMAKE_INSTALL_PREFIX=$(python3 -c "import sys; print(sys.prefix)") -D BUILD_EXAMPLES=ON -D PYTHON_EXECUTABLE=$(which python3) -D BUILD_opencv_java=OFF BUILD_opencv_test_java=OFF ..

        8.执行命令

sudo make install

        9.sudo make install 执行完毕后OpenCV编译过程就结束了，接下来就需要配置一些OpenCV的编译环境首先将OpenCV的库添加到路径，从而可以让系统找到

sudo gedit /etc/ld.so.conf.d/opencv.conf 

  执行此命令后打开的可能是一个空白的文件，不用管，只需要在文件末尾添加

/usr/local/lib  

        10.执行如下命令使得刚才的配置路径生效

sudo ldconfig

        11.配置bash

sudo gedit /etc/bash.bashrc  

  在最末尾添加

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig  
export PKG_CONFIG_PATH  

保存，执行如下命令使得配置生效

source /etc/bash.bashrc 

更新

sudo updatedb

        12.至此所有的配置都已经完成 

下面用一个小程序测试一下

找到 
cd到opencv-3.4.1/samples/cpp/example_cmake目录下 
我们可以看到这个目录里官方已经给出了一个cmake的example我们可以拿来测试下 

按顺序执行

cmake .
make
./opencv_example

即可看到打开了摄像头，在左上角有一个hello opencv 
即表示配置成功