opencv-120-二维码检测与识别

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知识点

OpenCV在对象检测模块中QRCodeDetector有两个相关API分别实现二维码检测与二维码解析:

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# 检测二维码
bool cv::QRCodeDetector::detect(
    InputArray img,
    OutputArray points 
)const
img输入图像，灰度或者彩色图像
points 得到的二维码四个点的坐标信息

# 解析二维码
std::string cv::QRCodeDetector::decode(
    InputArray img,
    InputArray points,
    OutputArray straight_qrcode = noArray() 
)
img输入图像，灰度或者彩色图像
points 二维码ROI最小外接矩形顶点坐标
qrcode 输出的是二维码区域ROI图像信息
返回的二维码utf-8字符串

上述两个API功能，可以通过一个API调用实现，该API如下：
std::string cv::QRCodeDetector::detectAndDecode(
    InputArray img,
    OutputArray points = noArray(),
    OutputArray straight_qrcode = noArray() 
)

代码（c++,python）

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

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
	Mat src = imread("D:/images/qrcode.png");
	imshow("image", src);
	Mat gray, qrcode_roi;
	cvtColor(src, gray, COLOR_BGR2GRAY);
	QRCodeDetector qrcode_detector;
	vector<Point> pts;
	string detect_info;
	bool det_result = qrcode_detector.detect(gray, pts);
	if (det_result) {
		detect_info = qrcode_detector.decode(gray, pts, qrcode_roi);
	}
	vector< vector<Point> > contours;
	contours.push_back(pts);
	drawContours(src, contours, 0, Scalar(0, 0, 255), 2);
	putText(src, detect_info.c_str(), Point(20, 200), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 0, 255), 2, 8);
	printf("qrcode info %s \n", detect_info.c_str());
	imshow("result", src);
	waitKey(0);
	return 0;
}
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"""
二维码检测与识别
"""

import cv2 as cv
import numpy as np

src = cv.imread("images/fanfan.jpg")
cv.imshow("image", src)
gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY)
qrcoder = cv.QRCodeDetector()
codeinfo, points, straight_qrcode = qrcoder.detectAndDecode(gray)
print(points)
result = np.copy(src)
cv.drawContours(result, [np.int32(points)], 0, (0, 0, 255), 2)
print("qrcode : %s" % codeinfo)
cv.imshow("result", result)
code_roi = np.uint8(straight_qrcode)
cv.namedWindow("qrcode roi", cv.WINDOW_NORMAL)
cv.imshow("qrcode roi", code_roi)

cv.waitKey(0)
cv.destroyAllWindows()

结果

代码地址

github