Ubuntu 16.04编译Opencv 3.4 (For python2.7 and python3.5)

相关依赖库的安装：
apt install python-pip python3-pip
pip2 install numpy
pip3 install numpy
apt-get install libpython2.7-dev libpython3.5-dev
apt-get install libgtk2.0-dev  (GTK+)
(可选先编译安装 ffmpeg-3.4.2, 这是一定要安装pkg-config)
OpenCV 3.4编译：
cmake -D CMAKE_BUILD_TYPE=RELEASE  \
    -D INSTALL_C_EXAMPLES=OFF \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D BUILD_EXAMPLES=OFF \
    -DENABLE_CXX11=ON \

    -D BUILD_opencv_python3=ON  \
    -D BUILD_opencv_python2=ON  \
    -D BUILD_opencv_java=OFF  \
    -D PYTHON3_EXECUTABLE=$(which python3)\
    -D PYTHON3_INCLUDE_DIR=/usr/include/python3.5m \
    -D PYTHON3_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1 \
    -D PYTHON3_NUMPY_PATH=/usr/local/lib/python3.5/dist-packages \
    -D PYTHON2_EXECUTABLE=$(which python2)\
    -D PYTHON2_INCLUDE_DIR=/usr/include/python2.7 \
    -D PYTHON2_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython2.7.so.1 \
    -D PYTHON2_NUMPY_PATH=/usr/local/lib/python2.7/dist-packages ..
最后make install
安装后验证：
python
root@houxn-OptiPlex-7040:#python
Python 2.7.12 (default, Dec 4 2017, 14:50:18)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'3.4.0'

root@houxn-OptiPlex-7040:#python3
Python 3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'3.4.0'

C++
g++ 时最后需要添加 `pkg-config opencv --cflags --libs`