Ubuntu 18.04 安裝OpenCV C++

構建并安裝

僅構建核心模塊

# 更新并安裝依賴
# 更新并安裝依賴
sudo apt update && sudo apt install -y cmake g++ wget unzip# 下載并解壓包
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
unzip opencv.zip# 創建構建目錄
mkdir build# 配置
cmake  ../opencv-master# 編譯
cmake --build . -j20

含有opencv-contrib構建

# 更新并安裝依賴
sudo apt update && sudo apt install -y cmake g++ wget unzip# 下載并解壓包
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# 創建并進入編譯目錄
mkdir -p build && cd build# 配置
cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-master/modules ../opencv-master# 編譯
cmake --build . -j20

安裝

構建完成之后，還需要進行安裝，直接在build目錄下安裝即可：

sudo make install

默認情況下，OpenCV 將安裝到該/usr/local目錄，所有文件將被復制到以下位置：

• /usr/local/bin - 可執行文件
• /usr/local/lib - lib (.so) 共享庫
• /usr/local/cmake/opencv4 - cmake 包
• /usr/local/include/opencv4 - 頭文件
• /usr/local/share/opencv4 - 其他文件（例如 XML 格式的訓練級聯）

由于/usr/local由 root 用戶擁有，因此需要 sudo執行安裝。

測試是否安裝成功

我們簡單地用Canny邊緣檢測算子來驗證OpenCV的安裝是否成功。

創建并進入一個測試目錄：

mkdir demo && cd demo

并在demo目錄隨意放一張測試圖像demo.jpg。

創建CMakeLists.txt文件并寫入以下內容：

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} )

創建demo.cpp文件并寫入以下內容：

#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));//運行canny算子Canny(edge, edge, 3, 4, 3);imwrite("Canny.jpg", edge);
}

然后執行：

cmake .
make
./demo

可以在demo目錄下看到原圖和邊緣圖像：

將OpenCV目錄添加到環境變量

想要在任何目錄下使用opencv，需在cmake之前將opencv的build目錄添加到環境變量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