opencv 轮廓检测 findContours drawContours

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

using namespace std;
using namespace cv;

int main()
{
	Mat  img, temp, temp2,dst, dstbin, distancetransform,rel, rel2;

	img = imread("lunkuo.jpg");

	resize(img, dst, Size(0, 0), 0.1, 0.1);
	//转为灰度图
	cvtColor(dst, temp, COLOR_BGR2GRAY);
	//高斯滤波
	GaussianBlur(temp, temp2, Size(3, 3), 5, 0);
	//二值化，找出目标区域
	threshold(temp2, dstbin, 200, 255, THRESH_BINARY);
	
	vector<vector<Point>> contours;
	vector<Vec4i> hierarchy;
	findContours(dstbin, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE,Point());
	drawContours(dst, contours, -1, Scalar(0, 0, 255));

	for (int i = 0; i < hierarchy.size(); i++)
	{
		cout << hierarchy[i] << endl;
	}
	for (int i = 0; i < contours.size(); i++)
	{
		double ar = contourArea(contours[i]);
		double len = arcLength(contours[i],true);
		string text = "序号：" + to_string(i) + " 面积：" + to_string(ar) + " 闭合长度：" + to_string(len);
		cout << text << endl;
		putText(dst, to_string(i), contours[i][i], FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0));

		//drawContours(dst, contours, i, Scalar(0, 0, 255));
		imshow("dst", dst);
		//waitKey(0);
	}

	waitKey(0);

	return 1;
}