为了便于本人查阅c++版本的opencv的查找轮廓的使用方法而写。下面是opencv的例子。
#include "opencv2/imgproc/imgproc.hpp" #include "opencv2/highgui/highgui.hpp" #include <math.h> #include <iostream> using namespace cv; using namespace std; static void help() { cout << "\nThis program illustrates the use of findContours and drawContours\n" << "The original image is put up along with the image of drawn contours\n" << "Usage:\n" << "./contours2\n" << "\nA trackbar is put up which controls the contour level from -3 to 3\n" << endl; } const int w = 500; int levels = 3; vector<vector<Point> > contours; vector<Vec4i> hierarchy; static void on_trackbar(int, void*) { Mat cnt_img = Mat::zeros(w, w, CV_8UC3); int _levels = levels - 3; drawContours( cnt_img, contours, _levels <= 0 ? 3 : -1, Scalar(128,255,255), 3, CV_AA, hierarchy, std::abs(_levels) ); imshow("contours", cnt_img); } int main( int argc, char**) { Mat img = Mat::zeros(w, w, CV_8UC1); if(argc > 1) { help(); // return -1; } //Draw 6 faces for( int i = 0; i < 6; i++ ) { int dx = (i%2)*250 - 30; int dy = (i/2)*150; const Scalar white = Scalar(255); const Scalar black = Scalar(0); if( i == 0 ) { for( int j = 0; j <= 10; j++ ) { double angle = (j+5)*CV_PI/21; line(img, Point(cvRound(dx+100+j*10-80*cos(angle)), cvRound(dy+100-90*sin(angle))), Point(cvRound(dx+100+j*10-30*cos(angle)), cvRound(dy+100-30*sin(angle))), white, 1, 8, 0); } } ellipse( img, Point(dx+150, dy+100), Size(100,70), 0, 0, 360, white, -1, 8, 0 ); ellipse( img, Point(dx+115, dy+70), Size(30,20), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+185, dy+70), Size(30,20), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+115, dy+70), Size(15,15), 0, 0, 360, white, -1, 8, 0 ); ellipse( img, Point(dx+185, dy+70), Size(15,15), 0, 0, 360, white, -1, 8, 0 ); ellipse( img, Point(dx+115, dy+70), Size(5,5), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+185, dy+70), Size(5,5), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+150, dy+100), Size(10,5), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+150, dy+150), Size(40,10), 0, 0, 360, black, -1, 8, 0 ); ellipse( img, Point(dx+27, dy+100), Size(20,35), 0, 0, 360, white, -1, 8, 0 ); ellipse( img, Point(dx+273, dy+100), Size(20,35), 0, 0, 360, white, -1, 8, 0 ); } //show the faces namedWindow( "image", 1 ); imshow( "image", img ); //Extract the contours so that vector<vector<Point> > contours0; findContours( img, contours0, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE); contours.resize(contours0.size()); for( size_t k = 0; k < contours0.size(); k++ ) approxPolyDP(Mat(contours0[k]), contours[k], 3, true); namedWindow( "contours", 1 ); createTrackbar( "levels+3", "contours", &levels, 7, on_trackbar ); on_trackbar(0,0); waitKey(); return 0; }