Ubuntu 18.04 安装OpenCV C++

构建并安装

仅构建核心模块

# 更新并安装依赖
# 更新并安装依赖
sudo apt update && sudo apt install -y cmake g++ wget unzip# 下载并解压包
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
unzip opencv.zip# 创建构建目录
mkdir build# 配置
cmake  ../opencv-master# 编译
cmake --build . -j20

含有opencv-contrib构建

# 更新并安装依赖
sudo apt update && sudo apt install -y cmake g++ wget unzip# 下载并解压包
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/master.zip
unzip opencv.zip
unzip opencv_contrib.zip# 创建并进入编译目录
mkdir -p build && cd build# 配置
cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-master/modules ../opencv-master# 编译
cmake --build . -j20

安装

构建完成之后，还需要进行安装，直接在build目录下安装即可：

sudo make install

默认情况下，OpenCV 将安装到该/usr/local目录，所有文件将被复制到以下位置：

• /usr/local/bin - 可执行文件
• /usr/local/lib - lib (.so) 共享库
• /usr/local/cmake/opencv4 - cmake 包
• /usr/local/include/opencv4 - 头文件
• /usr/local/share/opencv4 - 其他文件（例如 XML 格式的训练级联）

由于/usr/local由 root 用户拥有，因此需要 sudo执行安装。

测试是否安装成功

我们简单地用Canny边缘检测算子来验证OpenCV的安装是否成功。

创建并进入一个测试目录：

mkdir demo && cd demo

并在demo目录随意放一张测试图像demo.jpg。

创建CMakeLists.txt文件并写入以下内容：

cmake_minimum_required(VERSION 2.8)
project( demo )
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
add_executable( demo demo.cpp )
target_link_libraries( demo ${OpenCV_LIBS} )

创建demo.cpp文件并写入以下内容：

#include <opencv2/opencv.hpp>using namespace cv;int main(int argc, char** argv){Mat img = imread("./demo.jpg");Mat DstPic, edge, grayImage;DstPic.create(img.size(), img.type());cvtColor(img, grayImage, COLOR_BGR2GRAY);blur(grayImage, edge, Size(3, 3));//运行canny算子Canny(edge, edge, 3, 4, 3);imwrite("Canny.jpg", edge);
}

然后执行：

cmake .
make
./demo

可以在demo目录下看到原图和边缘图像：

将OpenCV目录添加到环境变量

想要在任何目录下使用opencv，需在cmake之前将opencv的build目录添加到环境变量OpenCV_DIR：

export OpenCV_DIR=[YOUR_PATH]/build

Ref:

https://docs.opencv.org/master/d7/d9f/tutorial_linux_install.html

https://blog.csdn.net/weixin_43953829/article/details/96473891

https://blog.csdn.net/qq_41323996/article/details/109469148?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522163297708716780255277403%2522%252C%2522scm%2522%253A%252220140713.130102334…%2522%257D&request_id=163297708716780255277403&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_allsobaiduend~default-1-109469148.pc_search_ecpm_flag&utm_term=%E5%8F%B2%E4%B8%8A%E6%9C%80%E5%85%A8OpenCV%E5%AE%89%E8%A3%85%E5%8F%8A%E9%94%99%E8%AF%AF%E8%A7%A3%E5%86%B3&spm=1018.2226.3001.4187
https://stackoverflow.com/questions/8711109/could-not-find-module-findopencv-cmake-error-in-configuration-process