Opencv4 QR code recognition test

OpenCV4 Two dimensional code recognition is introduced , Function is cv::QRCodeDetector, It's relatively simple to use , This paper is attached with c++ edition OpenCV QR code recognition program .
Measured results ：
Original picture ：

design sketch ：
The recognition result is ：123456789OCR

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

int main(int argc, char* argv[])
{
    
	// Image Reading 、 Preprocessing 
	cv::Mat img = cv::imread("1.png");
	cv::Mat gray;
	cv::cvtColor(img, gray, cv::COLOR_RGB2GRAY);

	// Instantiate the class of QR code 
	cv::QRCodeDetector QRdetecter;
	std::vector<cv::Point> list;
	cv::Mat  QR_img;

	// Perform QR code recognition 
	bool b =  QRdetecter.detect(gray, list);
	 //if (b)
	 //{
    
		// string str = QRdetecter.decode(gray, list);
		// std::cout <<" Recognition result ："<< str << std::endl;
	 //}

	std::string str = QRdetecter.detectAndDecode(gray, list, QR_img);
	std::cout  <<" Recognition result ："<< str << std::endl;

	// Draw QR code area 
	for (int j = 0; j < list.size(); j++)
	{
    
		if (j == 3)
			line(img, list[j], list[0], cv::Scalar(0, 255, 0), 2);
		else
			line(img, list[j], list[j + 1], cv::Scalar(0, 255, 0), 2);
	}

	// Show 
	cv::namedWindow("result_img", 0);
	imshow("result_img", img);
	if (QR_img.data)
	{
    
		cv::namedWindow("QR_img", 0);
		imshow("QR_img", QR_img);
	}
	cv::waitKey(0);

	return 0;
}