Linux安装OpenCV并配置VSCode环境

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安装环境
Ubuntu20.04

官方参考网址
OpenCV官网：https://opencv.org/
官方安装文档参考：https://docs.opencv.org/4.8.0/d7/d9f/tutorial_linux_install.html

安装OpenCV环境

安装必需工具

# cmake	  ->   构建工具
# g++	  ->   c++编译器
# unzip	  ->   zip文件解压工具
# libgtk2.0-dev pkg-config是图形界面支持的工具，不安装执行程序时会报错
sudo apt update && sudo apt install -y cmake g++ libgtk2.0-dev pkg-config wget unzip

下载并解压OpenCV库（Opencv Core Modules和opencv_contrib）

Opencv Core Modules: OpenCV的核心库模块是OpenCV的主要部分，包含了图像处理和计算机视觉方面的核心功能。
opencv_contrib:OpenCV的附加库，它包含了OpenCV官方贡献的扩展功能和算法，非必须安装的库文件，仅当需要使用该库时安装即可。

# 进入到安装目录,创建opencv父目录
cd ~	# 安装目录自选，如进入到根目录下的子目录，后面的命令前均需要添加sudo
mkdir opencv && cd opencv
wget -O opencv.zip https://github.com/opencv/opencv/archive/4.x.zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/4.x.zip
unzip opencv.zip
unzip opencv_contrib.zip
# 删除安装包
sudo rm -rf opencv*.zip

创建构建目录，进行构建

# 在opencv目录下创建build文件
mkdir -p build && cd build
# 配置构建的 opencv-4.x 和 opencv_contrib-4.x 项目的路径，
cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.x/modules ../opencv-4.x
# 构建当前目录下的CMake项目，--build 指定编译生成的文件存放目录，其中就包括可执行文件，. 表示存放到当前目录
cmake --build .

构建过程花费时间很长，我这边用了将近半个小时，需要耐心等待一下

验证构建结果

构建完成后，我们可以在build/lib路径下看到库文件，在build/bin路径下看到一些可执行的文件（样例，测试，apps等），运行以下指令可以查看上述文件是否存在

ls bin
ls lib

在build目录下看到CMake package files，运行以下指令可查看

ls OpenCVConfig*.cmake
ls OpenCVModules.cmake

安装

若上述检查无误，进行安装

sudo make install

按照默认设置，opencv会被安装到 /usr/local 目录下，所有的文件会被复制到以下位置:

/usr/local/bin - executable files
/usr/local/lib - libraries (.so)
/usr/local/cmake/opencv4 - cmake package
/usr/local/include/opencv4 - headers
/usr/local/share/opencv4 - other files (e.g. trained cascades in XML format)

opencv官方说明：安装过程只将文件复制到预定义的位置，并进行少量的修补。使用这种方法进行安装不会将opencv集成到系统包注册表中，因此，例如，opencv不能自动卸载。由于可能与系统包冲突，我们不建议普通用户进行全系统安装。

验证安装结果

使用opencv自带的samples验证即可

cd ~/opencv-4.x/samples/cpp/example_cmake	# 进入opencv核心库文件夹的samples下的cpp的案例文件中
# 构建
cmake .
# 编译并生成可执行文件
make
# 执行文件
./opencv_example

执行后，显示OpenCV的版本即代表安装成功

配置VSCode环境

创建项目文件

VSCode是基于文件夹管理项目，首先创建文件夹，使用VSCode打开同时创建Cpp文件（同级目录下添加一张图片，便于测试），cpp内容如下

#include<opencv2/opencv.hpp>
using namespace cv;
int main()
{Mat srcImage=imread("1.jpg");imshow("Origin",srcImage);waitKey(0);return 0;
}

安装C/C++拓展，点击拓展，自行搜索安装C/C++和C/C++ Extension Pack计科

修改配置信息

点击调试，选择创建launch.json文件

launch.json配置如下：

{// Use IntelliSense to learn about possible attributes.// Hover to view descriptions of existing attributes.// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387"version": "0.2.0","configurations": [{"name": "(gdb) Launch","type": "cppdbg","request": "launch","program": "${workspaceRoot}/${fileBasenameNoExtension}.main.out","args": [],"stopAtEntry": false,"cwd": "${workspaceRoot}","environment": [],"externalConsole": true,"MIMode": "gdb","setupCommands": [{"description": "Enable pretty-printing for gdb","text": "-enable-pretty-printing","ignoreFailures": true}],"preLaunchTask": "build"}]
}

点击允许，点击配置任务，选择使用模板创建tasks.json文件 > Others

tasks.json配置如下：

{// See https://go.microsoft.com/fwlink/?LinkId=733558// for the documentation about the tasks.json format"version": "2.0.0","tasks": [{"label": "build","type": "shell","command": "g++","args": ["-g","-std=c++11","${file}","-o","${fileBasenameNoExtension}.main.out","-I","/usr/local/include","-I","/usr/local/include/opencv4","-I","/usr/local/include/opencv4/opencv2","-L","/usr/local/lib","-l","opencv_core","-l","opencv_imgproc","-l","opencv_imgcodecs","-l","opencv_video","-l","opencv_ml","-l","opencv_highgui","-l","opencv_objdetect","-l","opencv_flann","-l","opencv_imgcodecs","-l","opencv_photo","-l","opencv_videoio"],"problemMatcher": {"owner": "cpp","fileLocation": ["relative","${workspaceFolder}"],"pattern": [{"regexp": "^([^\\\\s].*)\\\\((\\\\d+,\\\\d+)\\\\):\\\\s*(.*)$","file": 1,"location": 2,"message": 3}]},"group": {"kind": "build","isDefault": true}}]
}

Ctrl+Shift+P搜索找到Edit Configurations(JSON)/编辑配置(JSON)

c_cpp_properties.json配置如下：

{"configurations": [{"name": "Linux","includePath": ["${workspaceFolder}/**",// 添加头文件查找路径"/usr/include","/usr/local/include/**"],"defines": ["_DEBUG","UNICODE","_UNICODE"],"compilerPath": "/usr/bin/cpp","cStandard": "c11","cppStandard": "c++11","intelliSenseMode": "gcc-x64"}],"version": 4
}

执行程序

环境配置完成，回到项目，单击F5执行程序，运行成功

注：如运行后出现如下信息，则是没有安装libgtk2.0-dev和pkg-config，回到第一步，安装好所有工具重新进行构建、编辑、安装

terminate called after throwing an instance of 'cv::Exception'what():  OpenCV(4.8.0-dev) /usr/local/opencv/opencv-4.x/modules/highgui/src/window.cpp:1272: error: (-2:Unspecified error) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Cocoa support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function 'cvShowImage'