1 /** 2 * @function generalContours_demo2.cpp 3 * @brief Demo code to obtain ellipses and rotated rectangles that contain detected contours 4 * @author OpenCV team 5 */ 6 7 #include "opencv2/imgcodecs.hpp" 8 #include "opencv2/highgui/highgui.hpp" 9 #include "opencv2/imgproc/imgproc.hpp" 10 #include <iostream> 11 #include <stdio.h> 12 #include <stdlib.h> 13 14 using namespace cv; 15 using namespace std; 16 17 Mat src; Mat src_gray; 18 int thresh = 100; 19 int max_thresh = 255; 20 RNG rng(12345); 21 22 /// Function header 23 void thresh_callback(int, void* ); 24 25 /** 26 * @function main 27 */ 28 int main( int, char** argv ) 29 { 30 /// Load source image and convert it to gray 31 src = imread( argv[1], 1 ); 32 33 /// Convert image to gray and blur it 34 cvtColor( src, src_gray, COLOR_BGR2GRAY ); 35 blur( src_gray, src_gray, Size(3,3) ); 36 37 /// Create Window 38 const char* source_window = "Source"; 39 namedWindow( source_window, WINDOW_AUTOSIZE ); 40 imshow( source_window, src ); 41 42 createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback ); 43 thresh_callback( 0, 0 ); 44 45 waitKey(0); 46 return(0); 47 } 48 49 /** 50 * @function thresh_callback 51 */ 52 void thresh_callback(int, void* ) 53 { 54 Mat threshold_output; 55 vector<vector<Point> > contours; 56 vector<Vec4i> hierarchy; 57 58 /// Detect edges using Threshold 59 threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY ); 60 /// Find contours 61 findContours( threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0) ); 62 63 /// Find the rotated rectangles and ellipses for each contour 64 vector<RotatedRect> minRect( contours.size() ); 65 vector<RotatedRect> minEllipse( contours.size() ); 66 67 for( size_t i = 0; i < contours.size(); i++ ) 68 { minRect[i] = minAreaRect( Mat(contours[i]) ); 69 if( contours[i].size() > 5 ) 70 { minEllipse[i] = fitEllipse( Mat(contours[i]) ); } 71 } 72 73 /// Draw contours + rotated rects + ellipses 74 Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 ); 75 for( size_t i = 0; i< contours.size(); i++ ) 76 { 77 Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) ); 78 // contour 79 drawContours( drawing, contours, (int)i, color, 1, 8, vector<Vec4i>(), 0, Point() ); 80 // ellipse 81 ellipse( drawing, minEllipse[i], color, 2, 8 ); 82 // rotated rectangle 83 Point2f rect_points[4]; minRect[i].points( rect_points ); 84 for( int j = 0; j < 4; j++ ) 85 line( drawing, rect_points[j], rect_points[(j+1)%4], color, 1, 8 ); 86 } 87 88 /// Show in a window 89 namedWindow( "Contours", WINDOW_AUTOSIZE ); 90 imshow( "Contours", drawing ); 91 } 92
