OpenCV实现绘制轮廓外接矩形

void cv::findContours( InputOutputArray image, OutputArrayOfArrays contours, OutputArray hierarchy, int mode, int method, Point offset = Point()

（Rect cv::boundingRect( InputArray points )）

RotatedRect cv::minAreaRect( InputArray points )

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

using namespace std;
using namespace cv;


class EdgeDetection
{
    cv::Mat m_img;
    cv::Mat m_canny;
public:
    EdgeDetection(cv::Mat iamge);
    bool cannyProcess(unsigned int downThreshold,unsigned int upThreshold);
    bool getContours();

    ~EdgeDetection();
};

#include "EdgeDetection.h"

EdgeDetection::EdgeDetection(cv::Mat image)
{
    m_img = image;
}

bool EdgeDetection::cannyProcess(unsigned int downThreshold, unsigned int upThreshold)
{
    bool ret=true;

    if (m_img.empty())
    {
        ret = false;
    }

    cv::Canny(m_img, m_canny, downThreshold, upThreshold);
    cv::imshow("Canny", m_canny);

    return ret;
}

bool EdgeDetection::getContours()
{
    bool ret = true;
    if (m_canny.empty())
    {
        ret = false;
    }

    cv::Mat k = cv::getStructuringElement(cv::MORPH_RECT, cv::Size(3, 3), cv::Point(-1, -1));
    cv::dilate(m_canny, m_canny, k);
    imshow("dilate", m_canny);

    // 轮廓发现与绘制
    vector<vector<cv::Point> > contours;
    vector<Vec4i> hierarchy;
    findContours(m_canny, contours, cv::RETR_EXTERNAL, CHAIN_APPROX_SIMPLE, Point());

    for (size_t i = 0; i < contours.size();++i)
    {
        // 最大外接轮廓
        cv::Rect rect = cv::boundingRect(contours[i]);
        cv::rectangle(m_img,rect,cv::Scalar(0,255,0),2,LINE_8);


        // 最小外接轮廓
        RotatedRect rrt = minAreaRect(contours[i]);
        Point2f pts[4];
        rrt.points(pts);
        // 绘制旋转矩形与中心位置
        for (int i = 0; i < 4; i++) {
            line(m_img, pts[i % 4], pts[(i + 1) % 4], Scalar(0, 0, 255), 2, 8, 0);
        }
        Point2f cpt = rrt.center;
        circle(m_img, cpt, 2, Scalar(255, 0, 0), 2, 8, 0);
    }





    imshow("contours", m_img);
    return ret;
}

EdgeDetection::~EdgeDetection()
{
}

#include"EdgeDetection.h"
using namespace std;
using namespace cv;



int main(int argc, char* argv[])
{
    Mat src = imread("rect.jpg");
    if (src.empty())
    {
        cout << "image is empty" << endl;
        return -1;
    }

    imshow("input", src);

    EdgeDetection ed(src);

    ed.cannyProcess(80,160);
    ed.getContours();

    waitKey(0);
    return 0;
}