74 lines
2.0 KiB
C++
74 lines
2.0 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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static 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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static void help()
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{
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cout << "\n This program demonstrates connected components and use of the trackbar\n"
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"Usage: \n"
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" ./connected_components <image(stuff.jpg as default)>\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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}
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const char* keys =
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{
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"{1| |stuff.jpg|image for converting to a grayscale}"
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};
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int main( int argc, const char** argv )
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{
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help();
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CommandLineParser parser(argc, argv, keys);
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string inputImage = parser.get<string>("1");
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img = imread(inputImage.c_str(), 0);
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if(img.empty())
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{
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cout << "Could not read input image file: " << inputImage << endl;
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return -1;
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}
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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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