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background subtraction

I was using and testing MOG2 background subtraction and othres provided by opencv. But it looks like thsi function don't takes as still image as a background instead takes it every time. I want to use one single image as a background and than use forground image to be subracted and give the result. Isn't it possible using any opencv function? This is the code i was using to check the mog2 function:

include <iostream>

include <sstream>

include <opencv2 imgcodecs.hpp="">

include <opencv2 imgproc.hpp="">

include <opencv2 videoio.hpp="">

include <opencv2 highgui.hpp="">

include <opencv2 video.hpp="">

using namespace cv; using namespace std; const char* params = "{ help h | | Print usage }" "{ input | vtest.avi | Path to a video or a sequence of image }" "{ algo | MOG2 | Background subtraction method (KNN, MOG2) }"; int main(int argc, char* argv[]) { CommandLineParser parser(argc, argv, params); parser.about( "This program shows how to use background subtraction methods provided by " " OpenCV. You can process both videos and images.\n" ); if (parser.has("help")) { //print help information parser.printMessage(); } //create Background Subtractor objects Ptr<backgroundsubtractor> pBackSub; /if (parser.get<string>("algo") == "MOG2") pBackSub = createBackgroundSubtractorMOG2(); else pBackSub = createBackgroundSubtractorKNN();/ pBackSub = createBackgroundSubtractorMOG2();

VideoCapture cap;
if(!cap.open(0))
  return 0;

/*VideoCapture capture( samples::findFile( parser.get<String>("input") ) );
if (!capture.isOpened()){
    //error in opening the video input
    cerr << "Unable to open: " << parser.get<String>("input") << endl;
    return 0;
}*/

Mat frame, fgMask;
while (true) {
    cap >> frame;
    if (frame.empty())
        break;
    //update the background model
    pBackSub->apply(frame, fgMask);
    //get the frame number and write it on the current frame
    rectangle(frame, cv::Point(10, 2), cv::Point(100,20),
              cv::Scalar(255,255,255), -1);
    stringstream ss;
    ss << cap.get(CAP_PROP_POS_FRAMES);
    string frameNumberString = ss.str();
    putText(frame, frameNumberString.c_str(), cv::Point(15, 15),
            FONT_HERSHEY_SIMPLEX, 0.5 , cv::Scalar(0,0,0));
    //show the current frame and the fg masks
    imshow("Frame", frame);
    imshow("FG Mask", fgMask);
    //get the input from the keyboard
    int keyboard = waitKey(30);
    if (keyboard == 'q' || keyboard == 27)
        break;
}
return 0;

}

background subtraction

I was using and testing MOG2 background subtraction and othres provided by opencv. But it looks like thsi function don't takes as still image as a background instead takes it every time. I want to use one single image as a background and than use forground image to be subracted and give the result. Isn't it possible using any opencv function? This is the code i was using to check the mog2 function:

include <iostream>

include <sstream>

include <opencv2 imgcodecs.hpp="">

include <opencv2 imgproc.hpp="">

include <opencv2 videoio.hpp="">

include <opencv2 highgui.hpp="">

include <opencv2 video.hpp="">

#include <iostream>
#include <sstream>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/video.hpp>
using namespace cv;
using namespace std;
const char* params
    = "{ help h         |           | Print usage }"
      "{ input          | vtest.avi | Path to a video or a sequence of image }"
      "{ algo           | MOG2      | Background subtraction method (KNN, MOG2) }";
int main(int argc, char* argv[])
{
    CommandLineParser parser(argc, argv, params);
    parser.about( "This program shows how to use background subtraction methods provided by "
                  " OpenCV. You can process both videos and images.\n" );
    if (parser.has("help"))
    {
        //print help information
        parser.printMessage();
    }
    //create Background Subtractor objects
    Ptr<backgroundsubtractor> Ptr<BackgroundSubtractor> pBackSub;
    /if (parser.get<string>("algo") /*if (parser.get<String>("algo") == "MOG2")
        pBackSub = createBackgroundSubtractorMOG2();
    else
        pBackSub = createBackgroundSubtractorKNN();/
createBackgroundSubtractorKNN();*/
    pBackSub = createBackgroundSubtractorMOG2();

createBackgroundSubtractorMOG2();
 VideoCapture cap;
 if(!cap.open(0))
   return 0;

 /*VideoCapture capture( samples::findFile( parser.get<String>("input") ) );
 if (!capture.isOpened()){
     //error in opening the video input
     cerr << "Unable to open: " << parser.get<String>("input") << endl;
     return 0;
 }*/

 Mat frame, fgMask;
 while (true) {
     cap >> frame;
     if (frame.empty())
         break;
     //update the background model
     pBackSub->apply(frame, fgMask);
     //get the frame number and write it on the current frame
     rectangle(frame, cv::Point(10, 2), cv::Point(100,20),
               cv::Scalar(255,255,255), -1);
     stringstream ss;
     ss << cap.get(CAP_PROP_POS_FRAMES);
     string frameNumberString = ss.str();
     putText(frame, frameNumberString.c_str(), cv::Point(15, 15),
             FONT_HERSHEY_SIMPLEX, 0.5 , cv::Scalar(0,0,0));
     //show the current frame and the fg masks
     imshow("Frame", frame);
     imshow("FG Mask", fgMask);
     //get the input from the keyboard
     int keyboard = waitKey(30);
     if (keyboard == 'q' || keyboard == 27)
         break;
 }
 return 0;
}

}