#include <iostream> 
#include <opencv2/opencv.hpp> 
#include <opencv2/highgui/highgui.hpp> 
 
 
int main() 
{ 
	cv::VideoCapture camera(0); 
 
	if (!camera.isOpened()) 
	{ 
  		std::cerr << "[ERROR] Could not open the camera!" << std::endl; 
  		return 1; 
	} 
 
	cv::namedWindow("Webcam", cv::WINDOW_AUTOSIZE); 
 
 
	while(true) 
	{ 
		cv::Mat frame;
		camera >> frame; 
		cv::imshow("Webcam", frame);//normal
		//----------	grey
		cv::Mat frame_gray;
		cv::cvtColor(frame,frame_gray,cv::COLOR_BGR2GRAY);
		//cv::imshow("gray",frame_gray);//grey
 		//----------- treshold
 		cv::Mat frame_thresh; 
		threshold(frame_gray, frame_thresh, 150, 255, cv::THRESH_BINARY); 
		//cv::imshow("thresh", frame_thresh); 
		//----------- contour
		std::vector<std::vector<cv::Point>> contours; 
		std::vector<cv::Vec4i> hierarchy; 
		findContours(frame_thresh, contours, hierarchy, cv::RETR_TREE, cv::CHAIN_APPROX_NONE); 
 
		cv::Mat frame_contours = frame.clone(); 
		drawContours(frame_contours, contours, -1, cv::Scalar(0, 255, 0), 2); 
 
cv::imshow("contours", frame_contours);

 
  		if (cv::waitKey(30) >= 0) 
   			break; 
	} 
 
 	return 0; 
}