example1.c

KLT: An Implementation of the Kanade-Lucas-Tomasi Feature Tracker KLT: An Implementation of the

/**********************************************************************
Finds the 100 best features in an image, and tracks these
features to the next image.  Saves the feature
locations (before and after tracking) to text files and to PPM files, 
and prints the features to the screen.
**********************************************************************/

#include "pnmio.h"
#include "klt.h"

#ifdef WIN32
int RunExample1()
#else
int main()
#endif
{
  unsigned char *img1, *img2;
  KLT_TrackingContext tc;
  KLT_FeatureList fl;
  int nFeatures = 100;
  int ncols, nrows;
  int i;

  tc = KLTCreateTrackingContext();
  KLTPrintTrackingContext(tc);
  fl = KLTCreateFeatureList(nFeatures);

  img1 = pgmReadFile("img0.pgm", NULL, &ncols, &nrows);
  img2 = pgmReadFile("img1.pgm", NULL, &ncols, &nrows);

  KLTSelectGoodFeatures(tc, img1, ncols, nrows, fl);

  printf("\nIn first image:\n");
  for (i = 0 ; i < fl->nFeatures ; i++)  {
    printf("Feature #%d:  (%f,%f) with value of %d\n",
           i, fl->feature[i]->x, fl->feature[i]->y,
           fl->feature[i]->val);
  }

  KLTWriteFeatureListToPPM(fl, img1, ncols, nrows, "feat1.ppm");
  KLTWriteFeatureList(fl, "feat1.txt", "%3d");

  KLTTrackFeatures(tc, img1, img2, ncols, nrows, fl);

  printf("\nIn second image:\n");
  for (i = 0 ; i < fl->nFeatures ; i++)  {
    printf("Feature #%d:  (%f,%f) with value of %d\n",
           i, fl->feature[i]->x, fl->feature[i]->y,
           fl->feature[i]->val);
  }

  KLTWriteFeatureListToPPM(fl, img2, ncols, nrows, "feat2.ppm");
  KLTWriteFeatureList(fl, "feat2.fl", NULL);      /* binary file */
  KLTWriteFeatureList(fl, "feat2.txt", "%5.1f");  /* text file   */

  return 0;
}