C++ 结合 opencv读取图片与视频
一、安装opencv
- 操作系统: Linux(采用远程服务器主机进行代码编写）
- 需提前配置（安装）cmake
- 远程连接服务器进行操作, 直接新建立的终端输入
sudo apt install libopencv-dev
二 、配置文件准备
2.1 新建立文件夹
- 建立一个新的文件夹，并在文件夹下面建立如下面的子文件夹
- 其中CMakeLists.txt是txt形式的文件
- .vscode里面放的是配置文件
- media放的图片和视频
- output 是输出的文件夹路径
- src 放的是源代码cpp文件
2.2 .vscode文件下配置文件
（1）配置tasks.json文件
{
"version": "2.0.0",
"tasks": [
{
"type": "cppbuild",
"label": "cmake配置",
"command": "cmake",
"args": [
"-S .",
"-B build",
"-DCMAKE_BUILD_TYPE=Debug"
],
"options": {
"cwd": "${workspaceFolder}"
},
"problemMatcher": [
"$gcc"
],
"group": "build",
},
{
"type": "cppbuild",
"label": "CMake编译",
"command": "cmake",
"args": [
"--build",
"build",
],
"options": {
"cwd": "${workspaceFolder}"
},
"problemMatcher": [
"$gcc"
],
"group": "build",
"dependsOn": [
"CMake配置"
]
},
{
"type": "shell",
"label": "删除build目录",
"command": "rm -rf build",
"options": {
"cwd": "${workspaceFolder}"
},
"problemMatcher": [
"$gcc"
],
"group": "build",
},
{
"label": "运行可执行文件",
"type": "shell",
"command": "./build/demo_${fileBasenameNoExtension}",
"problemMatcher": [],
"group": {
"kind": "build",
"isDefault": true
},
"options": {
"cwd": "${workspaceFolder}"
},
"dependsOn": [
"cmake构建"
]
}
]
}
（1）配置launch.json
{
"version": "0.2.0",
"configurations": [
{
"name": "C++ Cmake Debug",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceFolder}/build/demo_${fileBasenameNoExtension}",
"args": [],
"stopAtEntry": false,
"cwd": "${workspaceFolder}",
"environment": [],
"externalConsole": false,
"MIMode": "gdb",
"miDebuggerPath": "/usr/bin/gdb",
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
}
],
"preLaunchTask": "CMake编译"
}
]
}
三 、src文件下代码编写
3.1 图片的读取和显示（代码文件:1.img.cpp）
- 在导入 #include"opencv2/opencv.hpp" 会出现错误, 鼠标点击头文件并按住ctrl键，界面会出现配置,添加配置即可, 配置文件自动生成放在.vscode文件下。
- 由于是远程服务器主机, 所以无法显示图片，只能另存为。
#include"opencv2/opencv.hpp"
#include<iostream>
int main(int argc, char** argv)
{
cv :: Mat image = cv :: imread("./media/cat.jpg");
if(image.empty())
{
std :: cout << "Could not read the image: " << std :: endl;
return 1;
}
std :: cout << "图片高度: " << image.rows << "图片宽度: " << image.cols << std :: endl;
std :: cout << "图片的 data: " << cv :: format(image, cv :: Formatter :: FMT_NUMPY) << std :: endl;
std :: cout << "图片的 data: " << cv :: format(image, cv :: Formatter :: FMT_PYTHON) << std :: endl;
cv :: Mat gray;
cv :: Mat hsv;
cv :: Mat rgb;
cv :: cvtColor(image, gray, cv :: COLOR_BGR2GRAY);
cv :: cvtColor(image, hsv, cv :: COLOR_BGR2HSV);
cv :: cvtColor(image, rgb, cv :: COLOR_BGR2RGB);
cv :: imwrite("./output/gray.jpg", gray);
return 0;
}
3.2 视频流的读取（代码文件:2.video.cpp）
#include"opencv2/opencv.hpp"
#include<iostream>
#include<gflags/gflags.h>
int main(int argc, char **argv)
{
gflags :: ParseCommandLineFlags(&argc, &argv, true);
cv :: VideoCapture capture("./media/dog.mp4");
if(!capture.isOpened())
{
std :: cout << "无法读取视频" << std :: endl;
return 1;
}
cv :: Mat frame;
cv :: Mat gray;
while(true)
{
capture.read(frame);
if(frame.empty())
{
std :: cout << "文件读取完毕: " << std :: endl;
break;
}
cv :: cvtColor(frame, gray, cv :: COLOR_BGR2GRAY);
cv :: imshow("raw demo", frame);
cv :: imshow("gray demo", gray);
int k = cv :: waitKey(30);
if(k == 27)
{
std :: cout << "退出" << std :: endl;
break;
}
}
return 0;
}
3.3 视频流的读取并保存（代码文件:3.write.cpp）
#include"opencv2/opencv.hpp"
#include<iostream>
#include<gflags/gflags.h>
int main(int argc, char **argv)
{
gflags :: ParseCommandLineFlags(&argc, &argv, true);
cv :: VideoCapture capture("./media/dog.mp4");
if(!capture.isOpened())
{
std :: cout << "无法读取视频" << std :: endl;
return 1;
}
int frame_width = capture.get(cv :: CAP_PROP_FRAME_WIDTH);
int frame_height = capture.get(cv :: CAP_PROP_FRAME_HEIGHT);
double fps = capture.get(cv :: CAP_PROP_FPS);
std :: cout << "图像宽度: " << frame_width << std :: endl;
std :: cout << "图像高度: " << frame_height << std :: endl;
std :: cout << "图像帧率: " << fps << std :: endl;
cv :: Mat frame;
cv :: Mat gray;
cv::VideoWriter writer("./output/record.avi", cv::VideoWriter::fourcc('M', 'J', 'P', 'G'), fps, cv::Size(frame_width, frame_height));
while(true)
{
capture.read(frame);
if(frame.empty())
{
std :: cout << "文件读取完毕: " << std :: endl;
break;
}
cv :: cvtColor(frame, gray, cv :: COLOR_BGR2GRAY);
writer.write(frame);
}
return 0;
}
四、cmake配置
# 最低版本要求
cmake_minimum_required(VERSION 3.10)
# 项目信息
project(opencv_demo)
# 使用find_package命令查找OpenCV库
find_package(OpenCV REQUIRED)
find_package(gflags REQUIRED)
if (OpenCV_FOUND)
message(STATUS "OpenCV library status:")
message(STATUS " version: ${OpenCV_VERSION}")
message(STATUS " libraries: ${OpenCV_LIBS}")
message(STATUS " include path: ${OpenCV_INCLUDE_DIRS}")
else()
message(FATAL_ERROR "Could not find OpenCV library")
endif()
# 添加头文件
include_directories(${
OpenCV_INCLUDE_DIRS} ${
gflags_INCLUDE_DIRS})
# 链接库
link_libraries(${
OpenCV_LIBS} ${
gflags_LIBRARIES})
# 添加可执行文件
add_executable(demo_1.img src/1.img.cpp)
add_executable(demo_2.video src/2.video.cpp)
add_executable(demo_3.write src/3.write.cpp)
五、运行
- 运行1.img.cpp，终端选项 – 运行任务
- 会出现下列界面， 依次点击 删除 build目录表，在选择终端 – 运行任务 – cmake 配置，结束后，在点击终端 – 运行任务 – CMake 编译
- 上述过程结束后，就会正常运行与输出1.img.cpp
- 输出后结果如图所示, 主要看 output 文件夹，可能和我下面不一样，因为我又在写其他的代码
