opencv connectedComponentsWithStates

这是一段从 opencv essential书里面来的代码，收藏起来以后可能有用。

#include <opencv2/core/utility.hpp>#include "opencv2/imgproc.hpp"#include "opencv2/highgui.hpp"#include <iostream>using namespace cv;using namespace std;Mat img;int threshval = 227;static void on_trackbar(int, void*){ Mat bw = threshval < 128 ? (img < threshval) : (img >  threshval); Mat labelImage(img.size(), CV_32S); Mat stats, centroids; int nLabels = connectedComponentsWithStats(bw, labelImage,  stats, centroids); // Show connected components with random colors std::vector<Vec3b> colors(nLabels); colors[0] = Vec3b(0, 0, 0);//background for(int label = 1; label < nLabels; ++label){ colors[label] = Vec3b( (rand()&200), (rand()&200),  (rand()&200) ); } Mat dst(img.size(), CV_8UC3); for(int r = 0; r < dst.rows; ++r){ for(int c = 0; c < dst.cols; ++c){ int label = labelImage.at<int>(r, c); Vec3b &pixel = dst.at<Vec3b>(r, c); pixel = colors[label]; } } // Text labels with area of each cc (except background) for (int i=1; i< nLabels;i++) { float a=stats.at<int>(i,CC_STAT_AREA); Point org(centroids.at<double>(i,0),  centroids.at<double>(i,1)); String txtarea; std::ostringstream buff; buff << a; txtarea=buff.str(); putText( dst, txtarea, org,FONT_HERSHEY_COMPLEX_SMALL, 1,  Scalar(255,255,255), 1);  } imshow( "Connected Components", dst );}int main( int argc, const char** argv ){ img = imread("stuff.jpg", 0); namedWindow( "Connected Components", 1 ); createTrackbar( "Threshold", "Connected Components",  &threshval, 255, on_trackbar ); on_trackbar(threshval, 0); waitKey(0); return 0;}