QR Code detect and decode - QR 코드 리더

It shows how to detect and decode a QR Code.

OpenCV에서 QR코드를 감지하고 내용을 확인할 수 있다.

#include <Windows.h>
#include <opencv2/opencv.hpp>
 
using namespace std;
using namespace cv;
 
int main()
{
    VideoCapture cap(0);
 
    if (!cap.isOpened()) {
        cerr << "Camera open failed." << endl;
 
        return -1;
    }
 
    QRCodeDetector detector;
 
    Mat frame;
    vector<Point> points;
    String msg;
 
    while (true) {
        cap >> frame;
 
        if (frame.empty()) {
            cerr << "Empty frame." << endl;
 
            break;
        }
 
        msg = detector.detectAndDecode(frame, points); // Both detects and decodes QR code.
 
        if (!msg.empty()) {
            polylines(frame, points, true, Scalar(0, 0, 255), 2);
            putText(frame, msg, Point(10, 30), FONT_HERSHEY_PLAIN, 2, Scalar(0, 0, 255), 2);
 
            if (msg.substr(0, 4) == "http") {
                imshow("QR Code", frame);
 
                if (MessageBox(NULL, (msg + " is a website address.\nDo you want to visit?").c_str(), "QR Code", MB_YESNO) == IDYES) {
                    ShellExecute(NULL, "open", msg.c_str(), NULL, NULL, SW_SHOW);
                    // Performs an operation on a specified file.
                }
                else {
                    continue;
                }
            }
        }
        else {
            putText(frame, "No QR code detected", Point(10, 30), FONT_HERSHEY_PLAIN, 2, Scalar(0, 0, 255), 2);
        }
 
        imshow("QR Code", frame);
 
        if (waitKey(10) == 27)
            break;
    }
 
    return 0;
}

Run the program. It says 'No QR code detected' at first.

QR code with a message.

QR code with a website address.

If the first 4 letters of the message are 'http', it opens the website with the default web browser.