Opencv解析二维码

Opencv4.0版本以后，引入了二维码定位+解码功能
以下代码实现基于opencv 4.5.0

• 代码实现

#include "opencv2/objdetect.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/imgcodecs.hpp"
#include <string>
#include <iostream>

using namespace std;
using namespace cv;

/**
 * @brief  解析图片，并标记二维码位置
 * @note   
 * @param  input: 输入图片
 * @retval 
 */
int runQR(Mat input)
{
    
    
    QRCodeDetector qrcode;
    vector<Point> corners;
    vector<cv::String> decode_info;

	corners.clear();
	decode_info.clear();

	// 开始解码
    TickMeter timer;
	timer.start();
	// 多个扫描
	bool result_detection = qrcode.detectAndDecodeMulti(input, decode_info, corners);
	// cout << "result_detection:" << result_detection << endl;

	// 单个扫描
	// string  code_detection = qrcode.detectAndDecode(input, corners);
	// cout << "code_detection:" << code_detection << endl;

	timer.stop();
    cout << "Decoder time: " << timer.getTimeSec()*1000.00 << "ms" << endl;


	if (result_detection > 0){
    
    
		// cout << "decode_info.size():" << decode_info.size() <<endl;
		
		// 将1维向量转为4维
		vector<vector<Point>> corners2;
		for (size_t i = 0; i < corners.size(); i+=4)
		{
    
    
			vector<Point> temp(corners.begin()+i,corners.begin()+i+4);
			// cout << "temp:" << temp << endl;
			corners2.push_back(temp);
		}
		// cout << "corners2:" << corners2.size() << endl;


		// 显示二维码定位
		for (size_t i = 0; i < corners2.size(); i++)
		{
    
    
			drawContours(input,corners2,i,Scalar(0,0,255),2);
			// imshow("QR dst", input); 
		}
		
		// 显示识别结果
		for (size_t i = 0; i < decode_info.size(); i++)
		{
    
    
			if(!decode_info[i].empty())
				cout << "Get QRcode:" << decode_info[i] <<endl;
			else
				cout << "err" << endl;
		}
	}else{
    
    
		cout << "decoder err" << endl;
		return -1;
	}

	return 0;
}


/**
 * @brief  二维码检测、解析
 * @note   
 * @param  argc: 
 * @param  *argv[]: 
 * @retval 
 */
int QRcode_decode(int argc, char *argv[])
{
    
    
    string in_file_name = "./QRcode.png";

	// 加载二维码图片
    Mat input = imread(in_file_name, IMREAD_COLOR);
    cout << "image info: " << input.size() 
		<< " (" << typeToString(input.type()) << ")"
        << endl;

	runQR(input);
	imshow("QR src", input);
#if 0
	// 打开摄像头捕获
	VideoCapture cap(0);
    if (!cap.isOpened()){
    
    
        cout << "Cannot open a camera" << endl;
        return 2;
    }
	for (;;)
    {
    
    
        Mat frame;
        cap >> frame;
        if (frame.empty())
        {
    
    
            cout << "End of video stream" << endl;
            break;
        }
		
		runQR(frame);
		imshow("QR src", frame);

		if(waitKey(100) == 27){
    
    
			cout << "'ESC' is pressed. Exiting..." << endl;
            break;
		}
	}
#endif
    
	cout << "=============================" << endl;
    cout << "Press any key to exit ..." << endl;
    waitKey(0);
    cout << "Exit." << endl;

    return 0;
}

• 运行

eric@eric-PC:~/Documents/work/linux-c/opencv_demo/demo$ ./main 
image info: [335 x 388] (CV_8UC3)
Decoder time: 24.3895ms
Get QRcode:1234567890
=============================
Press any key to exit ...
Exit.

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