How to play and detect an object using captured video in background subtractor model?

问题

everyone.! I am using opencv2.4.2. actually I am doing project on object detection. I tried using BackgroundSubtractorMOG model. But I am not able to load video file from my computer. While running on real time this below code for segmentation works fine. I have implemented using frame differencing method for object detection. Now I want to segment whole object from the background. I have static background. so can anybody help me in below code how to segment object from captured video. also how to load a video file? thank you.

      #include "stdafx.h"
      #include "opencv2/imgproc/imgproc.hpp"
       #include "opencv2/highgui/highgui.hpp"
       #include "opencv2/contrib/contrib.hpp"
       #include "conio.h"

      #include "time.h"
      #include "opencv/cvaux.hpp"
      #include "opencv2/core/core.hpp"
      #include "opencv2/calib3d/calib3d.hpp"

      using namespace std;
      using namespace cv;
  int main(int argc, char** argv)
 {
//IplImage* tmp_frame;
//std::string arg = argv[1];
//VideoCapture capture();
      cv::VideoCapture cap;

       /*CvCapture *cap =cvCaptureFromFile("S:\\offline object detection                 database\\SINGLE PERSON Database\\video4.avi");
      if(!cap){
        printf("Capture failure\n");
         return -1;
        }

        IplImage* frame=0;
        frame = cvQueryFrame(cap);           
         if(!frame)
return -1;*/



     bool update_bg_model = true;

    if( argc < 2 )
    cap.open(0);
    else
    cap.open(std::string(argv[1]));

    if( !cap.isOpened() )
   {
    printf("can not open camera or video file\n");
    return -1;
   }

    Mat tmp_frame, bgmask;

    cap >> tmp_frame;
    if(!tmp_frame.data)
    {


    printf("can not read data from the video source\n");
    return -1;
    }

     namedWindow("video", 1);
    namedWindow("segmented", 1);

    BackgroundSubtractorMOG bgsubtractor;

    for(;;)
   {
    //double t = (double)cvGetTickCount();
    cap >> tmp_frame;
    if( !tmp_frame.data )
        break;
    bgsubtractor(tmp_frame, bgmask, update_bg_model ? -1 : 0);
    //t = (double)cvGetTickCount() - t;
    //printf( "%d. %.1f\n", fr, t/(cvGetTickFrequency()*1000.) );
    imshow("video", tmp_frame);
    imshow("segmented", bgmask);
    char keycode = waitKey(30);
    if( keycode == 27 ) break;
    if( keycode == ' ' )
        update_bg_model = !update_bg_model;
     }

      return 0;
     }

回答1:

The video loading in opencv works for me. To load a video you can try something like this. Once you have captured frame you either do processing in the loop or can call a separate function.

std::cout<<"Video File "<<argv[1]<<std::endl;

cv::VideoCapture input_video(argv[1]);

namedWindow("My_Win",1);

Mat cap_img;

while(input_video.grab())
{
   if(input_video.retrieve(cap_img))
   {
     imshow("My_Win", cap_img);
     /* Once you have the image do all the processing here */
     /* Or Call your image processing function */
     waitKey(1);

   }
}

or You can do something

int main(int argc, char*argv[])
{

    char *my_file = "C:\\vid_an2\\desp_me.avi";
    std::cout<<"Video File "<<my_file<<std::endl;
    cv::VideoCapture input_video;

    if(input_video.open(my_file))
    {
         std::cout<<"Video file open "<<std::endl;
    }
    else
    {
        std::cout<<"Not able to Video file open "<<std::endl;

    }
    namedWindow("My_Win",1);
    namedWindow("Segemented", 1);
    Mat cap_img;
    for(;;)
    {
         input_video >> cap_img;
         imshow("My_Win", cap_img);
          waitKey(0);
    }
   return 0;
 }

来源：https://stackoverflow.com/questions/16185456/how-to-play-and-detect-an-object-using-captured-video-in-background-subtractor-m

标签

visual-c++

OpenCV

image-processing