OpenCVCpp

Murtaza Hassan

4h上手C++版Opencv_哔哩哔哩_bilibili

数字图像处理(c++ opencv)入门学习 - 知乎 (zhihu.com)

Installing OpenCV on Windows for C++

Step 1 Download and Install OpenCV

Downloading and Installing OpenCV: Releases - OpenCV

2024年1月11日，最新版的OpenCV是4.9.0，我下载了的版本是OpenCV-4.8.0。下载解压到一个文件夹中。

(base) PS D:\Dev\opencv480> dir
    目录: D:\Dev\opencv480
Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
d-----         2024/1/11     14:14                build
d-----         2024/1/11     14:14                sources
-a----         2023/6/28     20:57          11560 LICENSE.txt
-a----         2023/6/28     20:57          27913 LICENSE_FFMPEG.txt
-a----         2023/6/28     20:57            868 README.md.txt

Step 2 Environment Variables

Add bin folder to Environment Variables path: D:\Dev\opencv480\build\x64\vc16\bin, then restart the PC.s

Step3 New Visual Studio Project

1. Best VS setting(Cherno)

• Output Directory: $(SolutionDir)bin$(Platform)$(Configuration)\
• Intermediate Directory: $(SolutionDir)bin\intermediate$(Platform)$(Configuration)\

D:\userCode\IntroOpenCV\bin\Win32\Debug\

D:\userCode\IntroOpenCV\bin\intermediate\Win32\Debug\

2. Set the platform target to x64

on

Step 4 OpenCV configuration

Add Directories by going to Project-Properties-Configuration Properties

VC++ Directories
	1. Add Build Directories: D:\Dev\opencv480\build\include
	2. Add Library Directories: D:\Dev\opencv480\build\x64\vc16\lib
Linker Input
	1. Add Linker input: opencv_world480d.lib
	** d(opencv_world480d.lib) for debug 
	** without d(opencv_world480.lib) for release

Step 5 Test

#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgcodecs.hpp>
#include <iostream>
#include <string>

int main()
{
	std::string path = "./Resources/test.png";
	cv::Mat img = cv::imread(path);
	cv::imshow("Image", img);
	cv::waitKey(0);
	return 0;
}

Using VSCode and OpenCV in Windows

Installing OpenCV 4.8.0 on Ubuntu 20.04 for C++

reference:

• https://docs.opencv.org/4.x/d7/d9f/tutorial_linux_install.html
• https://blog.csdn.net/KIK9973/article/details/118830187
• https://www.cnblogs.com/booturbo/p/17399215.html

Source code downloading

1. Download opencv-4.8.0.zip Sources in https://opencv.org/releases/ or https://github.com/opencv/opencv/releases/tag/4.8.0
2. Download opencv_contrib-4.8.0.zip Sources in https://github.com/opencv/opencv_contrib/releases/tag/4.8.0
3. unzip opencv-4.8.0.zip && unzip opencv_contrib-4.8.0.zip

build

4. build opencv

# 先安装依赖环境
npu481@npu481-H310M:~/userdoc/mydownload$ sudo apt-get install build-essential
npu481@npu481-H310M:~/userdoc/mydownload$ sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev 

# 编译opencv
npu481@npu481-H310M:~/userdoc/mydownload$ mkdir -p build && cd build

npu481@npu481-H310M:~/userdoc/mydownload/build$ cmake -D CMAKE_INSTALL_PREFIX=/usr/local -D CMAKE_BUILD_TYPE=Release -D OPENCV_GENERATE_PKGCONFIG=ON -D OPENCV_ENABLE_NONFREE=True -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.8.0/modules ../opencv-4.8.0

npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo make -j6 # 6表示运行命令的个数

npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo make install # 编译成功后，在build目录下执行安装命令，等待安装完成

- CMAKE_INSTALL_PREFIX 是opencv的安装地址 默认安装在 `/usr/local`
- CMAKE_BUILD_TYPE 是opencv安装的版本，Release和Debug两种可选，默认安装Release
- OPENCV_ENABLE_NONFREE 是否使用部分被申请了专利的算方法 这里选True的话就可以使用了
- OPENCV_GENERATE_PKGCONFIG 强烈建议开启这个 设置为ON。OPENCV_GENERATE_PKGCONFIG因为opencv4默认不生成.pc文件，所以加上这句用于生成opencv4.pc文件，支持pkg-config功能。opencv4版本及以上，这里用ON。OpenCV安装后的各种头文件和库文件的路径信息都在这个配置文件中。
- OPENCV_EXTRA_MODULES_PATH: opencv_contrib-4.8.0/modules
- `../opencv-4.8.0`: 制定OpenCV源文件目录

- `/usr/local`: 安装位置
- `/usr/local/bin`: 可执行文件
- `/usr/local/lib`: 库文件（.so）
- `/usr/local/lib/cmake/opencv4`: camke包
- `/usr/local/lib/pkgconfig`: opencv4.pc的位置
- `/usr/local/include/opencv4/opencv2`: 头文件
- `/usr/local/share/opencv4`: 其他文件
- `/usr/local/share/licenses/opencv4`: 其他文件

5. environment config

• 修改etc/bash.bashrc

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。需要进行如下配置：

npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo find / -iname opencv4.pc
/usr/local/lib/pkgconfig/opencv4.pc


npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo gedit /etc/bash.bashrc

#在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
npu481@npu481-H310M:~/userdoc/mydownload/build$ source /etc/bash.bashrc

• check

npu481@npu481-H310M:~/userdoc/mydownload/build$ pkg-config --modversion opencv4
4.8.0

npu481@npu481-H310M:~/userdoc/mydownload/build$ pkg-config --libs opencv4
-L/usr/local/lib -lopencv_gapi -lopencv_stitching -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_dnn_objdetect -lopencv_dnn_superres -lopencv_dpm -lopencv_face -lopencv_fuzzy -lopencv_hfs -lopencv_img_hash -lopencv_intensity_transform -lopencv_line_descriptor -lopencv_mcc -lopencv_quality -lopencv_rapid -lopencv_reg -lopencv_rgbd -lopencv_saliency -lopencv_stereo -lopencv_structured_light -lopencv_phase_unwrapping -lopencv_superres -lopencv_optflow -lopencv_surface_matching -lopencv_tracking -lopencv_highgui -lopencv_datasets -lopencv_text -lopencv_plot -lopencv_videostab -lopencv_videoio -lopencv_wechat_qrcode -lopencv_xfeatures2d -lopencv_shape -lopencv_ml -lopencv_ximgproc -lopencv_video -lopencv_xobjdetect -lopencv_objdetect -lopencv_calib3d -lopencv_imgcodecs -lopencv_features2d -lopencv_dnn -lopencv_flann -lopencv_xphoto -lopencv_photo -lopencv_imgproc -lopencv_core

• 配置OpenCV的动态库环境

npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo gedit /etc/ld.so.conf.d/opencv.conf

# 添加lib路径 在 末尾 保存退出
/usr/local/lib
 
# 刷新动态库环境
npu481@npu481-H310M:~/userdoc/mydownload/build$ sudo ldconfig

6. 测试OpenCV

npu481@npu481-H310M:~/userdoc/mydownload$ cd opencv-4.8.0/samples/cpp/example_cmake/
npu481@npu481-H310M:~/userdoc/mydownload/opencv-4.8.0/samples/cpp/example_cmake$ mkdir build && cd build
npu481@npu481-H310M:~/userdoc/mydownload/opencv-4.8.0/samples/cpp/example_cmake/build$ cmake ..
npu481@npu481-H310M:~/userdoc/mydownload/opencv-4.8.0/samples/cpp/example_cmake/build$ make
npu481@npu481-H310M:~/userdoc/mydownload/opencv-4.8.0/samples/cpp/example_cmake/build$ ./opencv_example 

VSCode中配置OpenCV

reference: https://zhuanlan.zhihu.com/p/363035298

tasks.json

{
    // 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
        "tasks": [
                {
                    "type": "shell",
                    "label": "g++ build active file",   
                    "command": "g++",       
                    "args": [       
                        "-g",       
                        "-std=c++11", // 指定C++版本
                        "${file}",     
                        "-o",     
                        "${workspaceFolder}/main",       
                        "`pkg-config", "--cflags", "--libs", "opencv4`",       
                        "-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"
                    ],
                    "options": {
                        "cwd": "/usr/bin"
                    },
                    "group": { 
                        "kind": "build",       
                        "isDefault": true        
                    }        
                }
            ],
    "version": "2.0.0",
  }

c_cpp_properties.json

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/local/include/opencv4"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "compilerPath": "/usr/bin/g++",
            "cStandard": "c11",
            "cppStandard": "c++11",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}

launch.json

{
    // 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": "g++ build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/main",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceRoot}",
            // "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "g++ build active file",
            "miDebuggerPath": "/usr/bin/gdb"
        }
    ]
  }