OpenCV的安装和vscode的配置

在图像处理领域，OpenCV的使用是必不可少的，这里介绍一下OpenCV的安装及其在vscode中的配置

1.OpenCV的安装

（1）安装依赖

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

第三行的安装可能会出现无法定位包的错误，有三种解决方案
第一种：

sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
sudo apt update
sudo apt install libjasper1 libjasper-dev

这个我自己用是有效果的
第二种：

sudo add-apt-repository "deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ xenial main multiverse restricted universe"
sudo apt update
sudo apt install libjasper1 libjasper-dev

第三种：不用管，其实这个依赖对后续的使用影响不大，甚至可能有些淘汰了

（2）下载OpenCV源码

网站放在这里了：https://opencv.org/releases/，下载对应版本的source就OK了

（3）安装

先解压文件，这里我解压在/home目录下了

进入OpenCV文件夹，创建build目录

cd opencv4.5.5
mkdir build
cd ./build

之后是cmake步骤

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

再执行make指令

sudo make -j6  #数字取决于你电脑的进程数，数字越大，make越快
sudo make install

（4）环境配置

我们之前安装的时候 OPENCV_GENERATE_PKGCONFIG=ON 所以在/usr/local/lib/pkgconfig下生成了opencv4.pc文件，里面记录了OpenCV头文件、库文件的路径。这个文件注意一下，因为最后你如果出错，很有可能缺少了这个文件

sudo gedit /etc/bash.bashrc

#文件末尾添加以下内容 并保存
PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
export PKG_CONFIG_PATH

#更新
sudo updatedb
source /etc/bash.bashrc

#打开下列文件
sudo gedit /etc/ld.so.conf.d/opencv.conf 
 
# 添加lib路径,在末尾保存退出
/usr/local/lib
 
# 更新
sudo ldconfig

#终端输入以下两命令，显示正常则安装成功
pkg-config --modversion opencv4 #查看版本号
pkg-config --libs opencv4 #查看libs库

2.vscode的配置

先保证自己C++相关插件下载好
实现一个软连接

cd   /usr/local/include/
sudo  ln  -s   opencv4/opencv2   opencv2

配置以下三个文件
c_cpp_properties.json

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/local/include/",
                "/usr/include/"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "c17",
            "cppStandard": "gnu++14",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}

launch.json

{

    "version": "0.2.0",
    "configurations": [
        {
            "name": "g++ - Build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}/${fileBasenameNoExtension}",  //程序文件路径
            "args": [],  //程序运行需传入的参数
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": true,   //运行时是否显示控制台窗口
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: g++ build active file",
            "miDebuggerPath": "/usr/bin/gdb"
        }
    ]
}

tasks.json

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++ build active file",  /* 与launch.json文件里的preLaunchTask的内容保持一致 */
            "command": "/usr/bin/g++",
            "args": [
                "-std=c++11",
                "-g",
                //"${file}",   /* 编译单个文件 */
                "${fileDirname}/*.cpp",  /* 编译多个文件 */
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}",  /* 输出文件路径 */
 
                /* 项目所需的头文件路径 */
                "-I","${workspaceFolder}/",
                "-I","/usr/local/include/",
                "-I","/usr/local/include/opencv4/",
                "-I","/usr/local/include/opencv4/opencv2",
 
                /* 项目所需的库文件路径 */
                "-L", "/usr/local/lib",
 
                /* OpenCV的lib库 */
                "/usr/local/lib/libopencv_*",
 
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

就ok了