opencv安装

官网：https://opencv.org/releases/    https://docs.opencv.org/
以opencv-3.4.8为例，介绍opencv的Ubuntu安装方法

安装说明

OpenCV docs -> OpenCV Tutorials -> Introduction to OpenCV -> Installation in Linux
参考：https://docs.opencv.org/3.4.8/d7/d9f/tutorial_linux_install.html

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

可提前下载 ippicv_2019_lnx_intel64_general_20180723.tgz到~/Downloads下，以免安装过程在下载包时卡住：
https://github.com/opencv/opencv_3rdparty/tree/ippicv/master_20180723/ippicv

如下命令安装：

export OPENCV_IPPICV_URL=file:~/Downloads/

mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
make -j3
sudo make install
sudo ldconfig

#pkg-config --libs --cflags opencv
-I/usr/local/include/opencv -I/usr/local/include -L/usr/local/lib -lopencv_highgui -lopencv_shape -lopencv_superres -lopencv_stitching -lopencv_objdetect -lopencv_dnn -lopencv_ml -lopencv_videostab -lopencv_calib3d -lopencv_videoio -lopencv_imgcodecs -lopencv_features2d -lopencv_video -lopencv_photo -lopencv_imgproc -lopencv_flann -lopencv_core

验证
opencv-3.4.3/samples/cpp/example_cmake目录下，官方已经给出了一个cmake的example，我们可以拿来测试下。

cd samples/cpp/example_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。

参考：
1. 环境配置—Ubuntu 16.04 安装Opencv 3.4.3 https://www.jianshu.com/p/f646448da265