MultiTracker | OpenCV Multiple Object Tracking

      OpnCV MultiTracker used to track multiple object using existing single tracking algorithm like CSRT, MIL, KCF, TLD, GOTURN, MEDIANFLOW, MOSSE and BOOSTING

      For learn about Single tracking algorithm see the blog post OpenCV Object Tracking.

      In this blog post I am using TrackerCSRT object and supply to MultiTracker class which will track multiple object on video frame. The object need to track will select manually by user using mouse. This is done by the function selectROIs where user can select multiple object by dragging the mouse and then press Enter key to select next object, finally press Esc key for start tracking.

      Below code will show how it can achieve using OpenCV C++ interface.

C++ Code

   // create the MultiTracker
    MultiTracker trackers;

    // container for tracking objects
    vector objects;

    std::string video = "track.mp4";
    VideoCapture cap(video);

    Mat frame;
    cap >> frame;
    vector  ROIs;
    //Select object to totrack
    selectROIs("tracker",frame,ROIs);

    //quit when the tracked object(s) is not selected
    if(ROIs.size()<1)
      return ;

    // initialise the tracker
    std::vector < Ptr  > algorithms;
    for (size_t i = 0; i < ROIs.size(); i++)
    {
        Ptr tracker = TrackerCSRT::create();
        algorithms.push_back(tracker);
        objects.push_back(ROIs[i]);
      }

    trackers.add(algorithms,frame,objects);

    //  the tracking action
    printf("Start the tracking process, press ESC to quit.\n");
    for ( ;; ){
      cap >> frame;

      // quit the program if no more frame
      if(frame.rows==0 || frame.cols==0)
        break;

      //update the tracking result
      trackers.update(frame);

      // draw the tracked object
      for(unsigned i=0;i < trackers.getObjects().size();i++)
        rectangle( frame, trackers.getObjects()[i], Scalar( 0, 255, 0 ), 2, 1 );

      // show image with the tracked object
      imshow("tracker",frame);

      //quit on ESC key
      if(waitKey(1)==27)break;
    }

Demo