Linux（Ubuntu 18.04）中安装OpenCV + OpenCV_Contrib

从github中down下OPenCV + OpenCV_Contrib库，可以从https://github.com/opencv上下载（注意版本对应）

cd ~/<my_working_directory>
git clone https://github.com/opencv/opencv.git
git clone https://github.com/opencv/opencv_contrib.git

将opencv_contrib目录移到opencv目录下

添加opencv所需要的依赖库：

Required Packages

• GCC 4.4.x or later
• CMake 2.8.7 or higher
• Git
• GTK+2.x or higher, including headers (libgtk2.0-dev)
• pkg-config
• Python 2.6 or later and Numpy 1.5 or later with developer packages (python-dev, python-numpy)
• ffmpeg or libav development packages: libavcodec-dev, libavformat-dev, libswscale-dev（一些开发用视频解码）
• [optional] libtbb2 libtbb-dev
• [optional] libdc1394 2.x
• [optional] libjpeg-dev, libpng-dev, libtiff-dev, libjasper-dev, libdc1394-22-dev
• [optional] CUDA Toolkit 6.5 or higher

sudo apt-get install build-essential
sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

在使用命令

    sudo apt-get install libjaster-dev

出现：errorE: unable to locate libjasper-dev时，执行

sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
sudo apt update

进入opencv文件夹，打开terminal

mkdir build
cd build

cmake编译（后面的两个点不能丢）

cmake -D CMAKE_INSTALL_PREFIX=/usr/local -D CMAKE_BUILD_TYPE=Release -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules ..

make -j8

python
import cv2

如果出现"No module named cv2"，请执行

sudo apt-get install python-opencv