Opencv Mat函數只在未被引用時才起作用？

-1

這是我的代碼。我意識到我不需要cv ::這是爲intellisense。我正在Qt和opencv之間。在這裏，這是我的問題。在main（）我試圖引用takePicture（）;因爲它返回一個Mat框架，我試過cv :: Mat pic ;.這編譯好，但它從來沒有捕獲下一幀。它只是複製圖像，但是如果我輸入該函數，則每次都會抓取一個新幀。 請看if（input =='c'）的代碼註釋。那麼給了什麼？Opencv Mat函數只在未被引用時才起作用？

#include <opencv/cv.h> 
    #include "opencv2/highgui/highgui.hpp" 
    #include <string.h> 
    #include <iostream> 
    #include <time.h> 

    using namespace cv; 
    using namespace std; 

    char buffer[100]; 
    char input; 
    int c= 1; // counter 


    // time.h timestamp 
    const string currentDateTime() 
    { 
    time_t  now = time(0); 
    struct tm tstruct; 
    char  buf[80]; 
    tstruct = *localtime(&now); 
    strftime(buf, sizeof(buf),"%m/%d %X", &tstruct); 

    return buf; 
    } 

    // capture image 
    cv::Mat takePicture() { 

     cv::Mat frame; 
     VideoCapture cap(0); 

     while(!cap.isOpened()){ 
     cout << "cant connect to cam" << std::endl; 
     } 

     double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH); 
     double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT); 

     cap >> frame; 
     cv::resize(frame, frame, cv::Size(320, 240)); // resizes the image 

     cv::rectangle(frame, cv::Rect(0,228,130,20), 
     cv::Scalar(255,255,255), -1); // -1 fills the rect 

     cv::putText(frame, currentDateTime(), 
     cv::Point(0,240), 1,1, cv::Scalar(0,0,0),1); // adds time stamp 

     return frame; // returns frame 
    } 

    int main(int argc, char* argv[]) 
    { 
     cv::Mat pic; 
     pic = takePicture(); 


     while (1) 
     { 
      cout << "enter c to capture or q to quit"<<endl; 
      cin>> input; 

      if (input == 'c'){ 
       sprintf(buffer,"C://pics//image%d.jpg" ,c); 
       imwrite(buffer, takePicture()); // this works    
      //imwrite(buffer, pic);    // this doesn't 

       cout << buffer<<endl;  
       c++; // inc picture number  

      }else{ 

      if(input == 'q') 
      return -1; 
     } 
     }  
     return 0; 
    }

來源

2016-03-11 Will Meyers

這不是您的問題的答案，但我做了一些更改您的代碼。

我認爲這是更方便的方法。

#include "opencv2/highgui/highgui.hpp" 
#include "opencv2/imgproc/imgproc.hpp" 
#include <string.h> 
#include <iostream> 
#include <time.h> 

using namespace cv; 
using namespace std; 

char buffer[100]; 
char input; 
int c= 1; // counter 


// time.h timestamp 
const string currentDateTime() 
{ 
    time_t  now = time(0); 
    struct tm tstruct; 
    char  buf[80]; 
    tstruct = *localtime(&now); 
    strftime(buf, sizeof(buf),"%m/%d %X", &tstruct); 

    return buf; 
} 

// capture image 
Mat takePicture(VideoCapture cap) 
{ 
    Mat frame; 

    double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH); 
    double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT); 

    cap >> frame; 
    resize(frame, frame, Size(320, 240)); // resizes the image 

    rectangle(frame, Rect(0,228,130,20), 
       Scalar(255,255,255), -1); // -1 fills the rect 

    putText(frame, currentDateTime(), 
      Point(0,240), 1,1, Scalar(0,0,0),1); // adds time stamp 

    return frame; // returns frame 
} 

int main(int argc, char* argv[]) 
{ 
    VideoCapture cap(0); 
    if(!cap.isOpened()) 
    { 
     cout << "cant connect to cam" << std::endl; 
     return -1; 
    } 

    Mat pic; 


    cout << "enter c to capture or q to quit" << endl; 
    while (1) 
    { 
     pic = takePicture(cap); 
     imshow("Video Capture", pic); 
     int input = waitKey(30); 

     if (input == 'c') 
     { 
      sprintf(buffer,"C:/pics/image%d.jpg",c); 
      imwrite(buffer, pic); 

      cout << buffer<<endl; 
      c++; // inc picture number 

     } 
     else 
     { 

      if(input == 'q') 
       return -1; 
     } 
    } 
    return 0; 
}

來源

2016-03-11 22:31:55 sturkmen

沒有意義的是清理不工作的代碼。處理幀的速度要慢得多。我將不得不切換到C格式。我無需查看輸出或爲流程添加更多延遲。這需要在後臺運行。 –

pic = takePicture();應該在裏面。它從未更新。這就是爲什麼它只使用第一張圖片

來源

2016-03-11 22:39:56 Thesane

啊，這是什麼感謝:) –

Opencv Mat函數只在未被引用時才起作用？

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