opencv/samples/cpp/bgfg_segm.cpp

#include "opencv2/core/core.hpp"
#include "opencv2/video/background_segm.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <stdio.h>

using namespace cv;
using namespace std;

void help()
{
 printf("\nDo background segmentation, especially demonstrating the use of cvUpdateBGStatModel().\n"
"       Learns the background at the start and then segments.\n"
"       Learning is togged by the space key. Will read from file or camera\n"
"Usage: \n"
"       ./bgfg_segm [--file_name]=<input file, camera as defautl>\n\n");
}

//this is a sample for foreground detection functions
int main(int argc, const char** argv)
{
    help();

    CommandLineParser parser(argc, argv);

    string fileName = parser.get<string>("file_name", "0");
    VideoCapture cap;
    bool update_bg_model = true;


    if(fileName == "0" )
        cap.open(0);
    else
        cap.open(fileName.c_str());

    if( !cap.isOpened() )
    {
        help();
        printf("can not open camera or video file\n");
        return -1;
    }
    
    namedWindow("image", CV_WINDOW_NORMAL);
    namedWindow("foreground mask", CV_WINDOW_NORMAL);
    namedWindow("foreground image", CV_WINDOW_NORMAL);
    namedWindow("mean background image", CV_WINDOW_NORMAL);

    BackgroundSubtractorMOG2 bg_model;
    Mat img, fgmask, fgimg;

    for(;;)
    {
        cap >> img;
        
        if( img.empty() )
            break;
        
        if( fgimg.empty() )
          fgimg.create(img.size(), img.type());

        //update the model
        bg_model(img, fgmask, update_bg_model ? -1 : 0);

        fgimg = Scalar::all(0);
        img.copyTo(fgimg, fgmask);

        Mat bgimg;
        bg_model.getBackgroundImage(bgimg);

        imshow("image", img);
        imshow("foreground mask", fgmask);
        imshow("foreground image", fgimg);
        if(!bgimg.empty())
          imshow("mean background image", bgimg );

        char k = (char)waitKey(30);
        if( k == 27 ) break;
        if( k == ' ' )
        {
            update_bg_model = !update_bg_model;
            if(update_bg_model)
            	printf("Background update is on\n");
            else
            	printf("Background update is off\n");
        }
    }

    return 0;
}