OpenCV打开免驱摄像头并进行简单操作

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace std;
using namespace cv;


void ImgSmooth(const cv::Mat &image)
{
    cv::namedWindow("in",cv::WINDOW_AUTOSIZE);
    cv::namedWindow("out",cv::WINDOW_AUTOSIZE);

    cv::imshow("in",image);
    
    //读取像素点
    int x=16,y=32;
    cv::Vec3b intensity=image.at<cv::Vec3b>(y,x);
    uchar blue=intensity[0];
    uchar green=intensity[1];
    uchar red=intensity[2];
    std::cout<<(unsigned int)blue
    <<(unsigned int)green<<(unsigned int)red<<endl;

    
    cv::Mat img_gry,img_pyr,img_pyr2,img_cny;
    cv::cvtColor(image,img_gry,CV_RGB2GRAY);

    std::cout<<"gray pixel: "<<(unsigned int)img_gry.at<uchar>(y,x)<<endl;

    x/=4;y/=4;

    //高斯模糊以及降采样通过以下函数实现
    cv::pyrDown(img_gry,img_pyr);

    std::cout<<"Pyramid pixel: "<<(unsigned int)img_pyr.at<uchar>(y,x)<<endl;


   // cv::pyrDown(img_pyr,img_pyr2);
    cv::imshow("img_pyr",img_pyr);
    //边缘提取
    cv::Canny(img_pyr,img_cny,10,20,3,true);

    img_cny.at<uchar>(x,y)=128;

    cv::imshow("img_cny",img_cny);

    //矩阵
    cv::Mat out;
    //高斯核的大小必须是奇数，因为高斯卷积会在其覆盖区域的中心输出
    cv::GaussianBlur(image,out,cv::Size(3,3),3,3);
    cv::GaussianBlur(out,out,cv::Size(3,3),3,3);

    cv::imshow("out",out);
    
}

int main(int argc,char** argv)
{
      cv::VideoCapture inputVideo(0);
    //设置摄像头分辨率640*480 帧率30fps  
    inputVideo.set(CV_CAP_PROP_FRAME_HEIGHT, 1080);  
    inputVideo.set(CV_CAP_PROP_FRAME_WIDTH, 1920);  
    inputVideo.set(CV_CAP_PROP_FPS, 30.0); 
    if (!inputVideo.isOpened())
    {
        cout << "Could not open the input video " << endl;
        return -1;
    }

    Mat frame;
    char imgname[100]={0};
    int f = 0;

    while (1) 
    {
        inputVideo >> frame;  
        if (frame.empty()) break;        
        imshow("Camera", frame);
         ImgSmooth(frame);
        char key = waitKey(1);
       if (key == 27)break;
        if (key == 'q' || key == 'Q')
        {
           sprintf(imgname, "./%d.jpg", ++f);
           cv::imwrite(imgname, frame);    
        }
    }
    
    return 0;
}

#include "opencv2/highgui/highgui.hpp"
#include <opencv2/imgproc/imgproc.hpp>
#include <cstring>

int main(int argc,char** argv)
{
    //cv::namedWindow("example",cv::WINDOW_AUTOSIZE);
    cv::VideoCapture cap;
    cap.open(std::string(argv[1]));
    cv::Mat frame;
    for(;;)
    {
        cap>>frame;
        if(frame.empty())
            break;
        cv::imshow("in",frame);
        //接下来就可以对frame进行处理了
    cv::Mat img_gry;
    cv::cvtColor(frame,img_gry,CV_RGB2GRAY);
     cv::imshow("out",img_gry);
        if(cv::waitKey(33)>=0)
            break;
    }

   return 0;
}

cmake_minimum_required(VERSION 2.8.3)
project(img)

set(CMAKE_BUILD_TYPE "Release")
set(CMAKE_CXX_FLAGS "-std=c++11")
set(CMAKE_CXX_FLAGS_RELEASE "-O3 -Wall -g")


#set(OpenCV_DIR "/home/lyy/Linux_dependence/opencv-4.1.0/build")
find_package(OpenCV REQUIRED)
#add_executable(img  imgCatch.cpp)
#add_executable(img  imgshow.cpp)

add_executable(img  videoshow.cpp)
target_link_libraries(img ${catkin_LIBRARIES} ${OpenCV_LIBS})