opencv学习笔记，利用contourArea和arcLength检测物体的轮廓面积和周长

因之前的代码很多多余，学习的时候刚写的，现于2018/8/6更新：

源代码如下：

// 操作系统： Windows 10 64
// IDE版本：Visual Studio 2017
// OpenCV版本： 3.4

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include 
using namespace cv;
using namespace std;

//找轮廓
void findcontours()
{
	vector > g_vContours;
	vector g_vHierarchy;
	Mat srcimg = imread("1.jpg", 1);
	//Rect roi1(424, 315, 2000, 1400);
	//srcimg = srcimg(roi1);

	cvtColor(srcimg, srcimg, COLOR_BGR2GRAY);
	medianBlur(srcimg, srcimg, 5);
	threshold(srcimg, srcimg, 100, 255, CV_THRESH_BINARY_INV);
	Canny(srcimg, srcimg, 100, 255, 3);
	findContours(srcimg, g_vContours, g_vHierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));

	vector mu(g_vContours.size());                                                                   //计算矩 
	for (unsigned int i = 0; i < g_vContours.size(); i++)
	{
		mu[i] = moments(g_vContours[i], false);
	}
	vector mc(g_vContours.size());                                                                   //计算中心矩
	for (unsigned int i = 0; i < g_vContours.size(); i++)
	{
		mc[i] = Point2f(static_cast(mu[i].m10 / mu[i].m00), static_cast(mu[i].m01 / mu[i].m00));
	}

	Mat drawing = Mat::zeros(srcimg.size(), CV_8UC3);                                                         //绘制轮廓
	for (unsigned int i = 0; i< g_vContours.size(); i++)
	{
		Scalar color = Scalar(255, 0, 0);
		drawContours(drawing, g_vContours, i, color, 2, 8, g_vHierarchy, 0, Point());                         //绘制外层和内层轮廓
		circle(drawing, mc[i], 4, color, -1, 8, 0);
	}

	printf("\t 输出内容: 面积和轮廓长度\n");                                                                  //输出内容
	for (unsigned int i = 0; i< g_vContours.size(); i++)
	{
		printf(" 通过m00计算出轮廓[%d]的面积: (M_00) = %.2f \n计算出的面积=%.2f , 长度: %.2f \n", i, mu[i].m00, contourArea(g_vContours[i]), arcLength(g_vContours[i], true));
		Scalar color2 = Scalar(255, 255, 0);
		drawContours(drawing, g_vContours, i, color2, 2, 8, g_vHierarchy, 0, Point());
		circle(drawing, mc[i], 4, color2, -1, 8, 0);
	}
}

void main()
{
	findcontours();

	waitKey(0);
	system("pause");

}

 

检测的物体图片：

检测结果：