历史背景更新模型

#include<opencv2/opencv.hpp>
#include<iostream>
using namespace std;

IplImage*  mhi=NULL;
IplImage* silh=NULL;
IplImage**  buf=NULL;
const int  N=2;
int last=0;
const double MHI_DURATION = 1;

void update_mhi( IplImage* img, IplImage* dst, int diff_threshold)
{
    double timestamp = clock()/100.;
    CvSize size = cvSize(img->width,img->height);

    int idx1, idx2;
//    IplImage* pyr = cvCreateImage( cvSize((size.width &-2)/2, (size.height&-2)/2), 8, 1 );
//    IplImage* pyr = cvCreateImage( cvSize((size.width )/2, (size.height)/2), 8, 1 );

    //仅第一次进入循环时运行
    if( !mhi || mhi->width != size.width || mhi->height != size.height )
    {
        if( buf == 0 )
        {
            buf = (IplImage**)malloc(N*sizeof(buf[0]));//buf[0]为四个字节  buf大小申请为四个图片的大小
            memset( buf, 0, N*sizeof(buf[0])); //将fuf的全部内容置零
        }

        for(int  i = 0; i < N; i++ )
        {
            cvReleaseImage( &buf[i] );
            buf[i] = cvCreateImage( size, IPL_DEPTH_8U, 1 );
            cvZero( buf[i] );// clear Buffer Frame at the beginning
        }
        cvReleaseImage( &mhi );
        mhi = cvCreateImage( size, IPL_DEPTH_32F, 1 );
        cvZero( mhi ); // clear MHI at the beginning
    }


    cvCvtColor( img, buf[last], CV_BGR2GRAY ); // convert frame to grayscale

    idx1 = last;
    idx2 = (last + 1) % N; // index of (last - (N-1))th frame
    last = idx2;

    silh = buf[idx2];
    cvAbsDiff( buf[idx1], buf[idx2], silh ); // get difference between frames

    cvThreshold( silh, silh, diff_threshold, 255, CV_THRESH_BINARY );
    cvUpdateMotionHistory( silh, mhi, timestamp, MHI_DURATION );

    cvConvert( mhi, dst );
    cvSmooth( dst, dst, CV_MEDIAN, 3, 0, 0, 0 );

//    cvPyrDown( dst, pyr, CV_GAUSSIAN_5x5 );
//    cvDilate( pyr, pyr, 0, 1 );
//    cvPyrUp( pyr, dst, CV_GAUSSIAN_5x5 );
//    cvReleaseImage( &pyr );
    cvDilate( dst, dst, 0, 1 );
}

int main()
{
    CvCapture* pCapture =cvCreateFileCapture("video.avi");

    int numfrm=0;
    cvNamedWindow("video");
    cvNamedWindow("HISTORY");
    cvMoveWindow("video",0,0);
    cvMoveWindow("HISTORY",500,0);

    IplImage *pFrame=NULL;
    IplImage *motion=NULL;

      while(pFrame = cvQueryFrame( pCapture )) //遍历
      {
          numfrm++; //遍历
          if(!motion)
          {
              motion=cvCreateImage(cvSize(pFrame->width,pFrame->height),8,1);
              cvZero(motion);
              motion->origin=pFrame->origin;
          }
          update_mhi(pFrame,motion,60);
          cvShowImage("video",pFrame);
          cvShowImage("HISTORY",motion);

          if(cvWaitKey(300)==27)
              break;
      }

      cvReleaseImage(&pFrame);
      cvReleaseImage(&motion);
      cvReleaseImage( &silh );
      cvReleaseCapture(&pCapture);
      cvDestroyWindow("video");
      cvDestroyWindow("HISTORY");
      return 0;
}

 程序运行结果：