ubuntu18.04 opencv 获取摄像头 (C++/python) 双目摄像头

ubuntu18.04 opencv 获取摄像头 (C++/python)

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第一版:

// g++ opencv-camera.cpp -o a.out `pkg-config --cflags --libs opencv`
#include 
using namespace std;
using namespace cv;

int main() {
    VideoCapture cap(0);
    if (!cap.isOpened()) {
        cout << "Cannot open camera\n";
        return 1;
    }

    Mat frame;
    Mat gray;
    //namedWindow("live", WINDOW_AUTOSIZE); // 命名一個視窗，可不寫
    while (true) {
        // 擷取影像
        bool ret = cap.read(frame); // or cap >> frame;
        if (!ret) {
            cout << "Can't receive frame (stream end?). Exiting ...\n";
            break;
        }

        // 彩色轉灰階
        cvtColor(frame, gray, COLOR_BGR2GRAY);

        // 顯示圖片
        imshow("live", frame);
        //imshow("live", gray);

        // 按下 q 鍵離開迴圈
        if (waitKey(1) == 'q') {
            break;
        }
    }
    // VideoCapture 會自動在解構子裡釋放資源
    return 0;
}

结果:

---

第二版:

#include 
#include 
#include 
#include 
#include 
using namespace cv;
using namespace std;
int main(int, char**)
{
    Mat frame;
    //--- INITIALIZE VIDEOCAPTURE
    VideoCapture cap;
    // open the default camera using default API
    // cap.open(0);
    // OR advance usage: select any API backend
    int deviceID = 0;             // 0 = open default camera
    int apiID = cv::CAP_ANY;      // 0 = autodetect default API
    // open selected camera using selected API
    cap.open(deviceID, apiID);
    // check if we succeeded
    if (!cap.isOpened()) {
        cerr << "ERROR! Unable to open camera\n";
        return -1;
    }
    //--- GRAB AND WRITE LOOP
    cout << "Start grabbing" << endl
        << "Press any key to terminate" << endl;
    for (;;)
    {
        // wait for a new frame from camera and store it into 'frame'
        cap.read(frame);
        // check if we succeeded
        if (frame.empty()) {
            cerr << "ERROR! blank frame grabbed\n";
            break;
        }
        // show live and wait for a key with timeout long enough to show images
        imshow("Live", frame);
        if (waitKey(5) >= 0)
            break;
    }
    // the camera will be deinitialized automatically in VideoCapture destructor
    return 0;
}

结果:

参考:

1. https://anishdubey.com/read-write-display-video-opencv
2. https://docs.opencv.org/4.x/d8/dfe/classcv_1_1VideoCapture.html