71 lines
1.8 KiB
C++
71 lines
1.8 KiB
C++
#include <opencv2/imgproc/imgproc.hpp>
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#include <opencv2/highgui/highgui.hpp>
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#include <iostream>
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using namespace cv;
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using namespace std;
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Mat img;
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int threshval = 100;
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void help()
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{
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cout <<
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"\n This program demonstrates connected components and use of the trackbar\n"
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<< "\n"
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<< "Usage: ./connected_components <image>\n"
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<< "\n"
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<< "The image is converted to grayscale and displayed, another image has a trackbar\n"
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<< "that controls thresholding and thereby the extracted contours which are drawn in color\n"
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<< endl;
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}
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void on_trackbar(int, void*)
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{
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Mat bw = threshval < 128 ? (img < threshval) : (img > threshval);
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vector<vector<Point> > contours;
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vector<Vec4i> hierarchy;
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findContours( bw, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE );
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Mat dst = Mat::zeros(img.size(), CV_8UC3);
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if( !contours.empty() && !hierarchy.empty() )
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{
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// iterate through all the top-level contours,
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// draw each connected component with its own random color
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int idx = 0;
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for( ; idx >= 0; idx = hierarchy[idx][0] )
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{
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Scalar color( (rand()&255), (rand()&255), (rand()&255) );
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drawContours( dst, contours, idx, color, CV_FILLED, 8, hierarchy );
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}
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}
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imshow( "Connected Components", dst );
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}
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int main( int argc, char** argv )
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{
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// the first command line parameter
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if(argc != 2)
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{
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help();
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return -1;
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}
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if( !(img=imread(argc == 2 ? argv[1] : "stuff.jpg", 0)).data) //The ending 0 in imread converts the image to grayscale.
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return -1;
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namedWindow( "Image", 1 );
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imshow( "Image", img );
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namedWindow( "Connected Components", 1 );
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createTrackbar( "Threshold", "Connected Components", &threshval, 255, on_trackbar );
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on_trackbar(threshval, 0);
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waitKey(0);
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return 0;
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}
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