opencv findContours/drawContours检测图像中的轮廓

#include <opencv2/core/core.hpp>  
#include <opencv2/highgui/highgui.hpp> 
#include <opencv2/imgproc/imgproc.hpp> 
#include <opencv/cv.h>


using namespace cv;
using namespace std;

Mat src; Mat src_gray;
int thresh = 100;
int max_thresh = 255;
RNG rng(12345);

/// Function header
void thresh_callback(int, void*);

/** @function main */
int main(int argc, char** argv)
{
	/// 加载源图像
	src = imread("ee.jpg", 1);

	/// 转成灰度并模糊化降噪
	cvtColor(src, src_gray, CV_BGR2GRAY);
	blur(src_gray, src_gray, Size(3, 3));

	/// 创建窗体
	char* source_window = "Source";
	namedWindow(source_window, CV_WINDOW_AUTOSIZE);
	imshow(source_window, src);

	createTrackbar(" Canny thresh:", "Source", &thresh, max_thresh, thresh_callback);
	thresh_callback(0, 0);

	waitKey(0);
	return(0);
}

/** @function thresh_callback */
void thresh_callback(int, void*)
{
	Mat canny_output;
	vector<vector<Point> > contours;
	vector<Vec4i> hierarchy;

	/// 用Canny算子检测边缘
	Canny(src_gray, canny_output, thresh, thresh * 2, 3);
	/// 寻找轮廓
	findContours(canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));

	/// 绘出轮廓
	Mat drawing = Mat::zeros(canny_output.size(), CV_8UC3);
	for (int i = 0; i < contours.size(); i++)
	{
		Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
		drawContours(drawing, contours, i, color, 2, 8, hierarchy, 0, Point());
	}

	/// 在窗体中显示结果
	namedWindow("Contours", CV_WINDOW_AUTOSIZE);
	imshow("Contours", drawing);
}

转载自：

http://www.opencv.org.cn/opencvdoc/2.3.2/html/doc/tutorials/imgproc/shapedescriptors/find_contours/find_contours.html#find-contours