Pyramid Lucas-Kanade optical flow code

#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#include <stdio.h>


const int MAX_CORNERS = 500;
int main(int argc, char** argv) {
   // Initialize, load two images from the file system, and
   // allocate the images and other structures we will need for
   // results.
//
IplImage* imgA = cvLoadImage("OpticalFlow0.jpg",CV_LOAD_IMAGE_GRAYSCALE);
IplImage* imgB = cvLoadImage("OpticalFlow1.jpg",CV_LOAD_IMAGE_GRAYSCALE);
CvSize      img_sz    = cvGetSize( imgA );
int         win_size = 10;
IplImage* imgC = cvLoadImage("OpticalFlow1.jpg",CV_LOAD_IMAGE_UNCHANGED);

// The first thing we need to do is get the features
// we want to track.
//
IplImage* eig_image = cvCreateImage( img_sz, IPL_DEPTH_32F, 1 );
IplImage* tmp_image = cvCreateImage( img_sz, IPL_DEPTH_32F, 1 );
int              corner_count = MAX_CORNERS;
CvPoint2D32f* cornersA        = new CvPoint2D32f[ MAX_CORNERS ];
cvGoodFeaturesToTrack(
imgA,
eig_image,
tmp_image,
cornersA,
&corner_count,
0.01,
5.0,
0,
3,
0,
0.04
);
cvFindCornerSubPix(
imgA,
cornersA,
corner_count,
cvSize(win_size,win_size),
cvSize(-1,-1),
cvTermCriteria(CV_TERMCRIT_ITER|CV_TERMCRIT_EPS,20,0.03)
);
// Call the Lucas Kanade algorithm
//
char features_found[ MAX_CORNERS ];
float feature_errors[ MAX_CORNERS ];
CvSize pyr_sz = cvSize( imgA->width+8, imgB->height/3 );
IplImage* pyrA = cvCreateImage( pyr_sz, IPL_DEPTH_32F, 1 );
  IplImage* pyrB = cvCreateImage( pyr_sz, IPL_DEPTH_32F, 1 );
  CvPoint2D32f* cornersB        = new CvPoint2D32f[ MAX_CORNERS ];
  cvCalcOpticalFlowPyrLK(
     imgA,
     imgB,
     pyrA,
     pyrB,
     cornersA,
     cornersB,
     corner_count,
     cvSize( win_size,win_size ),
     5,
     features_found,
     feature_errors,
     cvTermCriteria( CV_TERMCRIT_ITER | CV_TERMCRIT_EPS, 20, .3 ),
     0
  );
  // Now make some image of what we are looking at:
  //
  for( int i=0; i<corner_count; i++ ) {
     if( features_found[i]==0|| feature_errors[i]>550 ) {
 //       printf("Error is %f/n",feature_errors[i]);
        continue;
     }
 //    printf("Got it/n");
     CvPoint p0 = cvPoint(
        cvRound( cornersA[i].x ),
        cvRound( cornersA[i].y )
     );
     CvPoint p1 = cvPoint(
        cvRound( cornersB[i].x ),
        cvRound( cornersB[i].y )
     );
     cvLine( imgC, p0, p1, CV_RGB(255,0,0),2 );
  }
  cvNamedWindow("ImageA",0);
  cvNamedWindow("ImageB",0);
  cvNamedWindow("LKpyr_OpticalFlow",0);
  cvShowImage("ImageA",imgA);
  cvShowImage("ImageB",imgB);
  cvShowImage("LKpyr_OpticalFlow",imgC);
  cvWaitKey(0);
  return 0;
}