opencv利用多边形逼近原理识别多边形和圆

  

   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      #include <iostream>
     
    
   

    

     

    
    

     

      #include <opencv2/opencv.hpp>
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      #define MATCHMETHOD TM_SQDIFF_NORMED//宏定义匹配模式
     
    
   

    

     

    
    

     

      using 
      namespace cv;
     
    
   

    

     

    
    

     

      using 
      namespace 
      std;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      int main(int argc, char** argv)
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     

      	Mat src = imread(
      "几何.jpg");
     
    
   

    

     

    
    

     

      	Mat src_gray, binary;
     
    
   

    

     

    
    

     

      	Mat Triangle = src.clone(), Rect = src.clone(), Circlar = src.clone(), Pentagon = src.clone();
     
    
   

    

     

    
    

     
	
      if (src.empty()) {
     
    
   

    

     

    
    

     
		
      printf(
      "Could not load image...");
     
    
   

    

     

    
    

     
		
      return 
      -1;
     
    
   

    

     

    
    

     

      	}
     
    
   

    

     

    
    

     

      	cv::imshow(
      "Input Image", src);
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	
      //二值化
     
    
   

    

     

    
    

     

      	cvtColor(src, src_gray, COLOR_BGR2GRAY);
     
    
   

    

     

    
    

     

      	threshold(src_gray, binary, 
      0, 
      255, THRESH_BINARY | THRESH_OTSU);
     
    
   

    

     

    
    

     

      	binary = ~binary;
     
    
   

    

     

    
    

     

      	cv::imshow(
      "binary", binary);
     
    
   

    

     

    
    

     
	
      //发现轮廓
     
    
   

    

     

    
    

     
	
      vector<
      vector<Point>> contours;
     
    
   

    

     

    
    

     
	
      vector<Point> point;
     
    
   

    

     

    
    

     
	
      vector<Vec4i> hireachy;
     
    
   

    

     

    
    

     

      	findContours(binary, contours, hireachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point());
     
    
   

    

     

    
    

     
	
      int a=
      0;
     
    
   

    

     

    
    

     
	
      int b=
      0;
     
    
   

    

     

    
    

     
	
      int c=
      0;
     
    
   

    

     

    
    

     
	
      int d=
      0;
     
    
   

    

     

    
    

     
	
      //绘制出所有轮廓
     
    
   

    

     

    
    

     
	
      for (
      size_t t = 
      0; t < contours.size(); t++)
     
    
   

    

     

    
    

     

      	{
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
		
      int epsilon = 
      0.01*arcLength(contours[t], 
      true);
     
    
   

    

     

    
    

     

      		approxPolyDP(contours[t], point, epsilon, 
      true);
     
    
   

    

     

    
    

     
		
      if (point.size() == 
      3)
     
    
   

    

     

    
    

     

      		{
     
    
   

    

     

    
    

     

      			drawContours(Triangle, contours, t, Scalar(
      0, 
      0, 
      0), 
      2, 
      8, Mat(), 
      0, Point());
      //dst必须先初始化
     
    
   

    

     

    
    

     

      			a++;
     
    
   

    

     

    
    

     

      		}
     
    
   

    

     

    
    

     
		
      else 
      if (point.size() == 
      4)
     
    
   

    

     

    
    

     

      		{
     
    
   

    

     

    
    

     

      			drawContours(Rect, contours, t, Scalar(
      0, 
      0, 
      0), 
      2, 
      8, Mat(), 
      0, Point());
      //dst必须先初始化
     
    
   

    

     

    
    

     

      			b++;
     
    
   

    

     

    
    

     

      		}
     
    
   

    

     

    
    

     
		
      else 
      if (point.size() == 
      5)
     
    
   

    

     

    
    

     

      		{
     
    
   

    

     

    
    

     

      			drawContours(Pentagon, contours, t, Scalar(
      0, 
      0, 
      0), 
      2, 
      8, Mat(), 
      0, Point());
      //dst必须先初始化
     
    
   

    

     

    
    

     

      			c++;
     
    
   

    

     

    
    

     

      		}
     
    
   

    

     

    
    

     
		
      else 
      if (point.size()>=
      10)
     
    
   

    

     

    
    

     

      		{
     
    
   

    

     

    
    

     

      			drawContours(Circlar, contours, t, Scalar(
      0, 
      0, 
      0), 
      2, 
      8, Mat(), 
      0, Point());
      //dst必须先初始化
     
    
   

    

     

    
    

     

      			d++;
     
    
   

    

     

    
    

     

      		}
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
		
     
    
   

    

     

    
    

     

      	}
     
    
   

    

     

    
    

     
	
      cout << 
      "三角形数目" << a << 
      endl;
     
    
   

    

     

    
    

     
	
      cout << 
      "四边形数目" << b << 
      endl;
     
    
   

    

     

    
    

     
	
      cout<< 
      "五边形数目" << c<< 
      endl;
     
    
   

    

     

    
    

     
	
      cout<<
      "圆形形数目" << d<< 
      endl;
     
    
   

    

     

    
    

     

      	imshow(
      "Triangle", Triangle);
     
    
   

    

     

    
    

     

      	imshow(
      "Pentagon", Pentagon);
     
    
   

    

     

    
    

     

      	imshow(
      "Rect", Rect);
     
    
   

    

     

    
    

     

      	imshow(
      "Circlar", Circlar);
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      	waitKey(
      0);
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	
      return 
      0;
     
    
   

    

     

    
    

     

      }