二维码定位代码 C++，OpenCV

转自：http://www.cnblogs.com/jsxyhelu/p/6579412.html

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>


using namespace cv;
using namespace std;


Mat src; Mat src_gray;


RNG rng(12345);
//Scalar colorful = CV_RGB(rng.uniform(0,255),rng.uniform(0,255),rng.uniform(0,255));


Point Center_cal(vector<vector<Point> > contours, int i)//找到所提取轮廓的中心点
{
    int centerx = 0, centery = 0, n = contours[i].size();
    //在提取的小正方形的边界上每隔周长个像素提取一个点的坐标，求所提取四个点的平均坐标（即为小正方形的大致中心）
    centerx = (contours[i][n / 4].x + contours[i][n * 2 / 4].x + contours[i][3 * n / 4].x + contours[i][n - 1].x) / 4;
    centery = (contours[i][n / 4].y + contours[i][n * 2 / 4].y + contours[i][3 * n / 4].y + contours[i][n - 1].y) / 4;
    Point point1 = Point(centerx, centery);
    return point1;
}

int main(int argc, char** argv[])
{


    src = imread("01.jpg", 1);
    Mat src_all = src.clone();

    cvtColor(src, src_gray, CV_BGR2GRAY);
    //  src_gray = Scalar::all(255) - src_gray;
    blur(src_gray, src_gray, Size(3, 3));
    equalizeHist(src_gray, src_gray);
    imshow("滤波后", src_gray);

    Scalar color = Scalar(1, 1, 255);
    Mat threshold_output;
    vector<vector<Point> > contours, contours2;
    vector<Vec4i> hierarchy;
    Mat drawing = Mat::zeros(src.size(), CV_8UC3);
    Mat drawing2 = Mat::zeros(src.size(), CV_8UC3);
    threshold(src_gray, threshold_output, 112, 255, THRESH_BINARY);
    //Canny(src_gray,threshold_output,136,196,3);
    //imshow("预处理后：",threshold_output);
    //寻找轮廓 
    //第一个参数是输入图像 2值化的
    //第二个参数是内存存储器，FindContours找到的轮廓放到内存里面。
    //第三个参数是层级，**[Next, Previous, First_Child, Parent]** 的vector
    //第四个参数是类型，采用树结构
    //第五个参数是节点拟合模式，这里是全部寻找
    findContours(threshold_output, contours, hierarchy, CV_RETR_TREE, CHAIN_APPROX_NONE, Point(0, 0));
    //CHAIN_APPROX_NONE全体,CV_CHAIN_APPROX_SIMPLE,,,RETR_TREE    RETR_EXTERNAL    RETR_LIST   RETR_CCOMP

    int c = 0, ic = 0, k = 0, area = 0;

    //程序的核心筛选
    int parentIdx = -1;
    for (int i = 0; i< contours.size(); i++)
    {
        if (hierarchy[i][2] != -1 && ic == 0)
        {
            parentIdx = i;
            ic++;
        }
        else if (hierarchy[i][2] != -1)
        {
            ic++;
        }
        else if (hierarchy[i][2] == -1)
        {
            ic = 0;
            parentIdx = -1;
        }

        if (ic >= 2)
        {
            contours2.push_back(contours[parentIdx]);
            drawContours(drawing, contours, parentIdx, CV_RGB(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255)), 1, 8);
            ic = 0;
            parentIdx = -1;
            area = contourArea(contours[i]);//得出一个二维码定位角的面积，以便计算其边长（area_side）（数据覆盖无所谓，三个定位角中任意一个数据都可以）
        }
        //cout<<"i= "<<i<<" hierarchy[i][2]= "<<hierarchy[i][2]<<" parentIdx= "<<parentIdx<<" ic= "<<ic<<endl;
    }


    for (int i = 0; i<contours2.size(); i++)
        drawContours(drawing2, contours2, i, CV_RGB(rng.uniform(100, 255), rng.uniform(100, 255), rng.uniform(100, 255)), -1, 4, hierarchy[k][2], 0, Point());


    Point point[3];
    for (int i = 0; i<contours2.size(); i++)
    {
        point[i] = Center_cal(contours2, i);
    }
    area = contourArea(contours2[1]);//为什么这一句和前面一句计算的面积不一样呢
    int area_side = cvRound(sqrt(double(area)));
    for (int i = 0; i<contours2.size(); i++)
    {
        line(drawing2, point[i%contours2.size()], point[(i + 1) % contours2.size()], color, area_side / 4, 8);
    }


    imshow("提取后", drawing2);
    printf("%d\n", contours.size());
    //imshow( "Contours", drawing );

    //接下来要框出这整个二维码
    Mat gray_all, threshold_output_all;
    vector<vector<Point> > contours_all;
    vector<Vec4i> hierarchy_all;
    cvtColor(drawing2, gray_all, CV_BGR2GRAY);


    threshold(gray_all, threshold_output_all, 45, 255, THRESH_BINARY);

    //表示只寻找最外层轮廓
    findContours(threshold_output_all, contours_all, hierarchy_all, RETR_EXTERNAL, CHAIN_APPROX_NONE, Point(0, 0));//RETR_EXTERNAL表示只寻找最外层轮廓

    //求最小包围矩形，斜的也可以哦
     RotatedRect rectPoint = minAreaRect(contours_all[0]);
    Point2f fourPoint2f[4];

    //将rectPoint变量中存储的坐标值放到 fourPoint的数组中
    rectPoint.points(fourPoint2f);


    for (int i = 0; i < 4; i++)
    {
        line(src_all, fourPoint2f[i % 4], fourPoint2f[(i + 1) % 4], Scalar(20, 21, 237), 3);
    }

    imshow("二维码", src_all);

    waitKey(0);
    return(0);
}