Ubuntu20.04.2.0下安装opencv4.5.2+opencv_contrib_ubuntu20.04安装opencv

1.进入系统下载opencv+opencv_contrib

下载地址：Releases - OpenCV

选择sources下载相应版本

解压文件，一版放到home/（用户名）/下

GitHub - opencv/opencv_contrib: Repository for OpenCV's extra modules:opencv_contrib

解压放在opencv文件夹下

2.安装Ubuntu下的opencv需要的依赖项

 安装最新的CMake，输入命令

sudo apt-get update
sudo apt-get upgrade
sudo apt install cmake

 安装opencv依赖项

sudo apt-get install build-essential libgtk2.0-dev libavcodec-dev libavformat-dev libjpeg-dev libswscale-dev libtiff5-dev

sudo apt-get install libgtk2.0-dev

sudo apt-get install pkg-config

sudo apt-get install libv4l-dev 
sudo apt-get install v4l2ucp
sudo apt-get install v4l-utils

3.编译和安装opencv

进入到opencv文件夹,输入命令

mkdir build
cd build

编译，安装

cmake -D CMAKE_INSTALL_PREFIX=/usr/local -D CMAKE_BUILD_TYPE=Release -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules -D WITH_LIBV4L=ON ..
sudo make -j4
sudo make install

4.环境配置

打开/etc/ld.so.conf

sudo gedit /etc/ld.so.conf

在文件中加上一行

include /usr/local/lib

 sudo ldconfig

打开 /etc/bash.bashrc 文件

sudo gedit /etc/bash.bashrc 

末尾加上

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
export PKG_CONFIG_PATH

再输入命令

source /etc/bash.bashrc

5.检验

输入命令

pkg-config opencv --modversion

如果最后一步报错为：
Package opencv was not found in the pkg-config search path.

cd /usr/local/lib
 
sudo mkdir pkgconfig
cd pkgconfig
sudo touch opencv.pc
sudo vim opencv.pc

如果出现

sudo: vim：找不到命令

输入下命令安装vim

    sudo apt install vim

 vim模式下 a 插入代码   esc 退出到上一层  :wq  保存退出

首先建一个新的文件夹：pkgconfig
然后cd到这个文件夹下，新建opencv.pc文件；
再打开opencv.pc文件，文件内输入

prefix=/usr/local
exec_prefix=${prefix}
includedir=${prefix}/include
libdir=${exec_prefix}/lib
 
Name: opencv
Description: The opencv library
Version:4.5.2
Cflags: -I${includedir}/opencv4
Libs: -L${libdir} -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann  -lopencv_core

其中version是你的opencv版本。
最后:wq保存退出。

转到 opencv-4.5.2/sample/cpp/example_cmake 目录下，打开终端

cmake .
make
./opencv_example

如果摄像头打开，左上角出现 Hello OpenCV 则证明安装成功

ubuntu下Qt配置opencv

1.新建一个mainwindow项目，在.pro项目文件中添加

INCLUDEPATH += /usr/local/include/opencv4/opencv2 \
               /usr/local/include/opencv4
 
LIBS += /usr/local/lib/libopencv_*

2.mian.cpp文件改为

#include "mainwindow.h"
#include <QApplication>
#include "opencv2/opencv.hpp"
 
using namespace cv;
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
 
    Mat image = imread("/home/tuya/img_data/barbara.bmp");
 
    imshow("test",image);
    waitKey(0);
 
    return a.exec();
}

编译运行，如果出现 “cannot open shared object file: No such file or directory”，这是因为编译器找不到安装后lib的路径，在终端输入命令

gedit /etc/ld.so.conf.d/opencv.conf

 创建一个opencv.conf文件，在文件中添加lib路径

/usr/local/lib

保存，再输入下命令，即可解决

sudo ldconfig -v

重新编译运行项目

ubuntu opencv卸载

在ubuntu终端命令行输入以下命令进入安装opencv的build目录并进行卸载操作。

sudo make uninstall