sift.c

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/*
Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
All rights reserved.

This file is part of the VLFeat library and is made available under
the terms of the BSD license (see the COPYING file).
*/

#define VL_SIFT_DRIVER_VERSION 0.1

#include "generic-driver.h"

#include <vl/generic.h>
#include <vl/stringop.h>
#include <vl/pgm.h>
#include <vl/sift.h>
#include <vl/getopt_long.h>

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

/* ----------------------------------------------------------------- */
/* help message */
char const help_message [] =
  "Usage: %s [options] files ...\n"
  "\n"
  "Options include:\n"
  " --verbose -v    Be verbose\n"
  " --help -h       Print this help message\n"
  " --output -o     Specify output file\n"
  " --frames        Specify frames file\n"
  " --descriptors   Specify descriptors file\n"
  " --meta          Specify meta file\n"
  " --gss           Specify Gaussian scale space files\n"
  " --octaves -O    Number of octaves\n"
  " --levels -S     Number of levels per octave\n"
  " --first-octave  Index of the first octave\n"
  " --edge-thresh   Specify the edge threshold\n"
  " --peak-thresh   Specift the peak threshold\n"
  " --magnif        Specify the magnification factor\n"
  " --read-frames   Specify a file from which to read frames\n"
  " --orientations  Force the computation of the orientations\n"
  "\n" ;

/* ----------------------------------------------------------------- */
/* long options codes */
enum {
  opt_meta = 1000,
  opt_frames,
  opt_descriptors,
  opt_gss,
  opt_first_octave,
  opt_edge_thresh,
  opt_peak_thresh,
  opt_magnif,
  opt_read_frames,
  opt_orientations
} ;

/* short options */
char const opts [] = "vhO:S:o:" ;

/* long options */
struct option const longopts [] = {
  { "verbose",         no_argument,            0,          'v'              },
  { "help",            no_argument,            0,          'h'              },
  { "octaves",         required_argument,      0,          'O'              },
  { "levels",          required_argument,      0,          'S'              },
  { "output",          required_argument,      0,          'o'              },
  { "meta",            optional_argument,      0,          opt_meta         },
  { "frames",          optional_argument,      0,          opt_frames       },
  { "descriptors",     optional_argument,      0,          opt_descriptors  },
  { "gss",             optional_argument,      0,          opt_gss          },
  { "first-octave",    required_argument,      0,          opt_first_octave },
  { "edge-thresh",     required_argument,      0,          opt_edge_thresh  },
  { "peak-thresh",     required_argument,      0,          opt_peak_thresh  },
  { "magnif",          required_argument,      0,          opt_magnif       },
  { "read-frames",     required_argument,      0,          opt_read_frames  },
  { "orientations",    no_argument,            0,          opt_orientations },
  { 0,                 0,                      0,          0                }
} ;

/* ----------------------------------------------------------------- */
static int
save_gss (VlSiftFilt * filt, VlFileMeta * fm, const char * basename,
          int verbose)
{
  char tmp [1024] ;
  int S = filt -> S ;
  int i ;
  int s, err = 0 ;
  int w, h ;
  int o = filt -> o_cur ;
  VlPgmImage pim ;
  vl_uint8 *buffer = 0 ;
  vl_size q ;

  if (! fm -> active) {
    return VL_ERR_OK ;
  }

  w = vl_sift_get_octave_width  (filt) ;
  h = vl_sift_get_octave_height (filt) ;

  pim.width     = w ;
  pim.height    = h ;
  pim.max_value = 255 ;
  pim.is_raw    = 1 ;

  buffer = malloc (sizeof(vl_uint8) * w * h) ;
  if (! buffer) {
    err = VL_ERR_ALLOC ;
    goto save_gss_quit ;
  }

  q = vl_string_copy (tmp, sizeof(tmp), basename) ;
  if (q >= sizeof(tmp)) {
    err = VL_ERR_OVERFLOW ;
    goto save_gss_quit ;
  }

  for (s = 0 ; s < S ; ++s) {
    vl_sift_pix * pt = vl_sift_get_octave (filt, s) ;

    /* conversion */
    for (i = 0 ; i < w * h ; ++i) {
      buffer [i] = (vl_uint8) pt [i] ;
    }

    /* save */
    snprintf(tmp + q, sizeof(tmp) - q, "_%02d_%03d", o, s) ;

    err = vl_file_meta_open (fm, tmp, "wb") ;
    if (err) goto save_gss_quit ;

    err = vl_pgm_insert (fm -> file, &pim, buffer) ;
    if (err) goto save_gss_quit ;

    if (verbose) {
      printf("sift: saved gss level to '%s'\n", fm -> name) ;
    }

    vl_file_meta_close (fm) ;
  }

 save_gss_quit : ;
  if (buffer) free (buffer) ;
  vl_file_meta_close (fm) ;
  return err ;
}

/* ----------------------------------------------------------------- */
int
korder (void const* a, void const* b) {
  double x = ((double*) a) [2] - ((double*) b) [2] ;
  if (x < 0) return -1 ;
  if (x > 0) return +1 ;
  return 0 ;
}

/* ---------------------------------------------------------------- */
int
main(int argc, char **argv)
{
  /* algorithm parameters */
  double   edge_thresh  = -1 ;
  double   peak_thresh  = -1 ;
  double   magnif       = -1 ;
  int      O = -1, S = 3, omin = -1 ;

  vl_bool  err    = VL_ERR_OK ;
  char     err_msg [1024] ;
  int      n ;
  int      exit_code          = 0 ;
  int      verbose            = 0 ;
  vl_bool  force_output       = 0 ;
  vl_bool  force_orientations = 0 ;

  VlFileMeta out  = {1, "%.sift",  VL_PROT_ASCII, "", 0} ;
  VlFileMeta frm  = {0, "%.frame", VL_PROT_ASCII, "", 0} ;
  VlFileMeta dsc  = {0, "%.descr", VL_PROT_ASCII, "", 0} ;
  VlFileMeta met  = {0, "%.meta",  VL_PROT_ASCII, "", 0} ;
  VlFileMeta gss  = {0, "%.pgm",   VL_PROT_ASCII, "", 0} ;
  VlFileMeta ifr  = {0, "%.frame", VL_PROT_ASCII, "", 0} ;

#define ERRF(msg, arg) {                                        \
    err = VL_ERR_BAD_ARG ;                                      \
    snprintf(err_msg, sizeof(err_msg), msg, arg) ;              \
    break ;                                                     \
  }

#define ERR(msg) {                                              \
    err = VL_ERR_BAD_ARG ;                                      \
    snprintf(err_msg, sizeof(err_msg), msg) ;                   \
    break ;                                                     \
}

  /* -----------------------------------------------------------------
   *                                                     Parse options
   * -------------------------------------------------------------- */

  while (!err) {
    int ch = getopt_long(argc, argv, opts, longopts, 0) ;

    /* If there are no files passed as input, print the help and settings */
    if (ch == -1 && argc - optind == 0)
      ch = 'h';

    /* end of option list? */
    if (ch == -1) break;

    switch (ch) {

    case '?' :
      /* unkown option ............................................ */
      ERRF("Invalid option '%s'.", argv [optind - 1]) ;
      break ;

    case ':' :
      /* missing argument ......................................... */
      ERRF("Missing mandatory argument for option '%s'.",
          argv [optind - 1]) ;
      break ;

    case 'h' :
      /* --help ................................................... */
      printf (help_message, argv [0]) ;
      printf ("SIFT         filespec: `%s'\n", out.pattern) ;
      printf ("Frames       filespec: `%s'\n", frm.pattern) ;
      printf ("Descriptors  filespec: `%s'\n", dsc.pattern) ;
      printf ("Meta         filespec: `%s'\n", met.pattern) ;
      printf ("GSS          filespec: '%s'\n", gss.pattern) ;
      printf ("Read frames  filespec: '%s'\n", ifr.pattern) ;
      printf ("Version: driver %s; libvl %s\n",
              VL_XSTRINGIFY(VL_SIFT_DRIVER_VERSION),
              vl_get_version_string()) ;
      exit (0) ;
      break ;

    case 'v' :
      /* --verbose ................................................ */
      ++ verbose ;
      break ;

    case 'o' :
      /* --output  ................................................ */
      err = vl_file_meta_parse (&out, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;
      force_output = 1 ;
      break ;

    case opt_frames :
      /* --frames  ................................................ */
      err = vl_file_meta_parse (&frm, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;
      break ;

    case opt_descriptors :
      /* --descriptor ............................................. */
      err = vl_file_meta_parse (&dsc, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;
      break;

    case opt_meta :
      /* --meta ................................................... */
      err = vl_file_meta_parse (&met, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;

      if (met.protocol != VL_PROT_ASCII)
        ERR("meta file supports only ASCII protocol") ;
      break ;

    case opt_read_frames :
      /* --read_frames ............................................ */
      err = vl_file_meta_parse (&ifr, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;
      break ;

    case opt_gss :
      /* --gss .................................................... */
      err = vl_file_meta_parse (&gss, optarg) ;
      if (err)
        ERRF("The arguments of '%s' is invalid.", argv [optind - 1]) ;
      break ;



    case 'O' :
      /* --octaves ............................................... */
      n = sscanf (optarg, "%d", &O) ;
      if (n == 0 || O < 0)
        ERRF("The argument of '%s' must be a non-negative integer.",
            argv [optind - 1]) ;
      break ;

    case 'S' :
      /* --levels ............................................... */
      n = sscanf (optarg, "%d", &S) ;
      if (n == 0 || S < 0)
        ERRF("The argument of '%s' must be a non-negative integer.",
            argv [optind - 1]) ;
      break ;

    case opt_first_octave :
      /* --first-octave ......................................... */
      n = sscanf (optarg, "%d", &omin) ;
      if (n == 0)
        ERRF("The argument of '%s' must be an integer.",
            argv [optind - 1]) ;
      break ;



    case opt_edge_thresh :
      /* --edge-thresh ........................................... */
      n = sscanf (optarg, "%lf", &edge_thresh) ;
      if (n == 0 || edge_thresh < 1)
        ERRF("The argument of '%s' must be not smaller than 1.",
            argv [optind - 1]) ;
      break ;

    case opt_peak_thresh :
      /* --edge-thresh ........................................... */
      n = sscanf (optarg, "%lf", &peak_thresh) ;
      if (n == 0 || peak_thresh < 0)
        ERRF("The argument of '%s' must be a non-negative float.",
            argv [optind - 1]) ;
      break ;

    case opt_magnif :
      /* --magnif  .............................................. */
      n = sscanf (optarg, "%lf", &magnif) ;
      if (n == 0 || magnif < 1)
        ERRF("The argument of '%s' must be a non-negative float.",
            argv [optind - 1]) ;
      break ;


    case opt_orientations :
      /* --orientations ......................................... */
      force_orientations = 1 ;
      break ;

    case 0 :
    default :
      /* should not get here ...................................... */
      abort() ;
    }
  }

  /* check for parsing errors */
  if (err) {
    fprintf(stderr, "%s: error: %s (%d)\n",
            argv [0],
            err_msg, err) ;
    exit (1) ;
  }

  /* parse other arguments (filenames) */
  argc -= optind ;
  argv += optind ;

  /*
     if --output is not specified, specifying --frames or --descriptors
     prevent the aggregate outout file to be produced.
  */
  if (! force_output && (frm.active || dsc.active)) {
    out.active = 0 ;
  }

  if (verbose > 1) {
#define PRNFO(name,fm)                                                  \
    printf("sift: " name) ;                                             \
    printf("%3s ",  (fm).active ? "yes" : "no") ;                       \
    printf("%-6s ", vl_string_protocol_name ((fm).protocol)) ;          \
    printf("%-10s\n", (fm).pattern) ;

    PRNFO("write aggregate . ", out) ;
    PRNFO("write frames .... ", frm) ;
    PRNFO("write descriptors ", dsc) ;
    PRNFO("write meta ...... ", met) ;
    PRNFO("write GSS ....... ", gss) ;
    PRNFO("read  frames .... ", ifr) ;

    if (force_orientations)
      printf("sift: will compute orientations\n") ;
  }

  /* ------------------------------------------------------------------
   *                                         Process one image per time
   * --------------------------------------------------------------- */

  while (argc--) {

    char             basename [1024] ;
    char const      *name = *argv++ ;

    FILE            *in    = 0 ;
    vl_uint8        *data  = 0 ;
    vl_sift_pix     *fdata = 0 ;
    VlPgmImage       pim ;

    VlSiftFilt      *filt = 0 ;
    vl_size          q ;
    int              i ;
    vl_bool          first ;

    double           *ikeys = 0 ;
    int              nikeys = 0, ikeys_size = 0 ;

    /* ...............................................................
     *                                                 Determine files
     * ............................................................ */

    /* get basenmae from filename */
    q = vl_string_basename (basename, sizeof(basename), name, 1) ;

    err = (q >= sizeof(basename)) ;

    if (err) {
      snprintf(err_msg, sizeof(err_msg),
               "Basename of '%s' is too long", name);
      err = VL_ERR_OVERFLOW ;
      goto done ;
    }

    if (verbose) {
      printf ("sift: <== '%s'\n", name) ;
    }

    if (verbose > 1) {
      printf ("sift: basename is '%s'\n", basename) ;
    }

    /* open input file */
    in = fopen (name, "rb") ;
    if (!in) {
      err = VL_ERR_IO ;
      snprintf(err_msg, sizeof(err_msg),
               "Could not open '%s' for reading.", name) ;
      goto done ;
    }

    /* ...............................................................
     *                                                       Read data
     * ............................................................ */

    /* read PGM header */
    err = vl_pgm_extract_head (in, &pim) ;

    if (err) {
      switch (vl_get_last_error()) {
      case  VL_ERR_PGM_IO :
        snprintf(err_msg, sizeof(err_msg),
                 "Cannot read from '%s'.", name) ;
        err = VL_ERR_IO ;
        break ;

      case VL_ERR_PGM_INV_HEAD :
        snprintf(err_msg, sizeof(err_msg),
                 "'%s' contains a malformed PGM header.", name) ;
        err = VL_ERR_IO ;
        goto done ;
      }
    }

    if (verbose)
      printf ("sift: image is %" VL_FMT_SIZE " by %" VL_FMT_SIZE " pixels\n",
              pim. width,
              pim. height) ;

    /* allocate buffer */
    data  = malloc(vl_pgm_get_npixels (&pim) *
                   vl_pgm_get_bpp       (&pim) * sizeof (vl_uint8)   ) ;
    fdata = malloc(vl_pgm_get_npixels (&pim) *
                   vl_pgm_get_bpp       (&pim) * sizeof (vl_sift_pix)) ;

    if (!data || !fdata) {
      err = VL_ERR_ALLOC ;
      snprintf(err_msg, sizeof(err_msg),
               "Could not allocate enough memory.") ;
      goto done ;
    }

    /* read PGM body */
    err  = vl_pgm_extract_data (in, &pim, data) ;

    if (err) {
      snprintf(err_msg, sizeof(err_msg), "PGM body malformed.") ;
      err = VL_ERR_IO ;
      goto done ;
    }

    /* convert data type */
    for (q = 0 ; q < (unsigned) (pim.width * pim.height) ; ++q) {
      fdata [q] = data [q] ;
    }

    /* ...............................................................
     *                                     Optionally source keypoints
     * ............................................................ */

#define WERR(name,op)                                           \
    if (err == VL_ERR_OVERFLOW) {                               \
      snprintf(err_msg, sizeof(err_msg),                        \
               "Output file name too long.") ;                  \
      goto done ;                                               \
    } else if (err) {                                           \
      snprintf(err_msg, sizeof(err_msg),                        \
               "Could not open '%s' for " #op, name) ;          \
      goto done ;                                               \
    }

    if (ifr.active) {

      /* open file */
      err = vl_file_meta_open (&ifr, basename, "rb") ;
      WERR(ifr.name, reading) ;

#define QERR                                                            \
      if (err ) {                                                       \
        snprintf (err_msg, sizeof(err_msg),                             \
                  "'%s' malformed", ifr.name) ;                         \
        err = VL_ERR_IO ;                                               \
        goto done ;                                                     \
      }

      while (1) {
        double x, y, s, th ;

        /* read next guy */
        err = vl_file_meta_get_double (&ifr, &x) ;
        if   (err == VL_ERR_EOF) break;
        else QERR ;
        err = vl_file_meta_get_double (&ifr, &y ) ; QERR ;
        err = vl_file_meta_get_double (&ifr, &s ) ; QERR ;
        err = vl_file_meta_get_double (&ifr, &th) ;
        if   (err == VL_ERR_EOF) break;
        else QERR ;

        /* make enough space */
        if (ikeys_size < nikeys + 1) {
          ikeys_size += 10000 ;
          ikeys       = realloc (ikeys, 4 * sizeof(double) * ikeys_size) ;
        }

        /* add the guy to the buffer */
        ikeys [4 * nikeys + 0]  = x ;
        ikeys [4 * nikeys + 1]  = y ;
        ikeys [4 * nikeys + 2]  = s ;
        ikeys [4 * nikeys + 3]  = th ;

        ++ nikeys ;
      }

      /* now order by scale */
      qsort (ikeys, nikeys, 4 * sizeof(double), korder) ;

      if (verbose) {
        printf ("sift: read %d keypoints from '%s'\n", nikeys, ifr.name) ;
      }

      /* close file */
      vl_file_meta_close (&ifr) ;
    }

    /* ...............................................................
     *                                               Open output files
     * ............................................................ */

    err = vl_file_meta_open (&out, basename, "wb") ; WERR(out.name, writing) ;
    err = vl_file_meta_open (&dsc, basename, "wb") ; WERR(dsc.name, writing) ;
    err = vl_file_meta_open (&frm, basename, "wb") ; WERR(frm.name, writing) ;
    err = vl_file_meta_open (&met, basename, "wb") ; WERR(met.name, writing) ;

    if (verbose > 1) {
      if (out.active) printf("sift: writing all ....... to . '%s'\n", out.name);
      if (frm.active) printf("sift: writing frames .... to . '%s'\n", frm.name);
      if (dsc.active) printf("sift: writing descriptors to . '%s'\n", dsc.name);
      if (met.active) printf("sift: writign meta ...... to . '%s'\n", met.name);
    }

    /* ...............................................................
     *                                                     Make filter
     * ............................................................ */

    filt = vl_sift_new (pim.width, pim.height, O, S, omin) ;

    if (edge_thresh >= 0) vl_sift_set_edge_thresh (filt, edge_thresh) ;
    if (peak_thresh >= 0) vl_sift_set_peak_thresh (filt, peak_thresh) ;
    if (magnif      >= 0) vl_sift_set_magnif      (filt, magnif) ;

    if (!filt) {
      snprintf (err_msg, sizeof(err_msg),
                "Could not create SIFT filter.") ;
      err = VL_ERR_ALLOC ;
      goto done ;
    }

    if (verbose > 1) {
      printf ("sift: filter settings:\n") ;
      printf ("sift:   octaves      (O)     = %d\n",
              vl_sift_get_noctaves     (filt)) ;
      printf ("sift:   levels       (S)     = %d\n",
              vl_sift_get_nlevels      (filt)) ;
      printf ("sift:   first octave (o_min) = %d\n",
              vl_sift_get_octave_first (filt)) ;
      printf ("sift:   edge thresh           = %g\n",
              vl_sift_get_edge_thresh  (filt)) ;
      printf ("sift:   peak thresh           = %g\n",
              vl_sift_get_peak_thresh  (filt)) ;
      printf ("sift:   magnif                = %g\n",
              vl_sift_get_magnif       (filt)) ;
      printf ("sift: will source frames? %s\n",
              ikeys ? "yes" : "no") ;
      printf ("sift: will force orientations? %s\n",
              force_orientations ? "yes" : "no") ;
    }

    /* ...............................................................
     *                                             Process each octave
     * ............................................................ */
    i     = 0 ;
    first = 1 ;
    while (1) {
      VlSiftKeypoint const *keys = 0 ;
      int                   nkeys ;

      /* calculate the GSS for the next octave .................... */
      if (first) {
        first = 0 ;
        err = vl_sift_process_first_octave (filt, fdata) ;
      } else {
        err = vl_sift_process_next_octave  (filt) ;
      }

      if (err) {
        err = VL_ERR_OK ;
        break ;
      }

      if (verbose > 1) {
        printf("sift: GSS octave %d computed\n",
               vl_sift_get_octave_index (filt));
      }

      /* optionally save GSS */
      if (gss.active) {
        err = save_gss (filt, &gss, basename, verbose) ;
        if (err) {
          snprintf (err_msg, sizeof(err_msg),
                    "Could not write GSS to PGM file.") ;
          goto done ;
        }
      }

      /* run detector ............................................. */
      if (ikeys == 0) {
        vl_sift_detect (filt) ;

        keys  = vl_sift_get_keypoints     (filt) ;
        nkeys = vl_sift_get_nkeypoints (filt) ;
        i     = 0 ;

        if (verbose > 1) {
          printf ("sift: detected %d (unoriented) keypoints\n", nkeys) ;
        }
      } else {
        nkeys = nikeys ;
      }

      /* for each keypoint ........................................ */
      for (; i < nkeys ; ++i) {
        double                angles [4] ;
        int                   nangles ;
        VlSiftKeypoint        ik ;
        VlSiftKeypoint const *k ;

        /* obtain keypoint orientations ........................... */
        if (ikeys) {
          vl_sift_keypoint_init (filt, &ik,
                                 ikeys [4 * i + 0],
                                 ikeys [4 * i + 1],
                                 ikeys [4 * i + 2]) ;

          if (ik.o != vl_sift_get_octave_index (filt)) {
            break ;
          }

          k          = &ik ;

          /* optionally compute orientations too */
          if (force_orientations) {
            nangles = vl_sift_calc_keypoint_orientations
              (filt, angles, k) ;
          } else {
            angles [0] = ikeys [4 * i + 3] ;
            nangles    = 1 ;
          }
        } else {
          k = keys + i ;
          nangles = vl_sift_calc_keypoint_orientations
            (filt, angles, k) ;
        }

        /* for each orientation ................................... */
        for (q = 0 ; q < (unsigned) nangles ; ++q) {
          vl_sift_pix descr [128] ;

          /* compute descriptor (if necessary) */
          if (out.active || dsc.active) {
            vl_sift_calc_keypoint_descriptor
              (filt, descr, k, angles [q]) ;
          }

          if (out.active) {
            int l ;
            vl_file_meta_put_double (&out, k -> x     ) ;
            vl_file_meta_put_double (&out, k -> y     ) ;
            vl_file_meta_put_double (&out, k -> sigma ) ;
            vl_file_meta_put_double (&out, angles [q] ) ;
            for (l = 0 ; l < 128 ; ++l) {
              vl_file_meta_put_uint8 (&out, (vl_uint8) (512.0 * descr [l])) ;
            }
            if (out.protocol == VL_PROT_ASCII) fprintf(out.file, "\n") ;
          }

          if (frm.active) {
            vl_file_meta_put_double (&frm, k -> x     ) ;
            vl_file_meta_put_double (&frm, k -> y     ) ;
            vl_file_meta_put_double (&frm, k -> sigma ) ;
            vl_file_meta_put_double (&frm, angles [q] ) ;
            if (frm.protocol == VL_PROT_ASCII) fprintf(frm.file, "\n") ;
          }

          if (dsc.active) {
            int l ;
            for (l = 0 ; l < 128 ; ++l) {
              double x = 512.0 * descr[l] ;
              x = (x < 255.0) ? x : 255.0 ;
              vl_file_meta_put_uint8 (&dsc, (vl_uint8) (x)) ;
            }
            if (dsc.protocol == VL_PROT_ASCII) fprintf(dsc.file, "\n") ;
          }
        }
      }
    }

    /* ...............................................................
     *                                                       Finish up
     * ............................................................ */

    if (met.active) {
      fprintf(met.file, "<sift\n") ;
      fprintf(met.file, "  input       = '%s'\n", name) ;
      if (dsc.active) {
        fprintf(met.file, "  descriptors = '%s'\n", dsc.name) ;
      }
      if (frm.active) {
        fprintf(met.file,"  frames      = '%s'\n", frm.name) ;
      }
      fprintf(met.file, ">\n") ;
    }

  done :
    /* release input keys buffer */
    if (ikeys) {
      free (ikeys) ;
      ikeys_size = nikeys = 0 ;
      ikeys = 0 ;
    }

    /* release filter */
    if (filt) {
      vl_sift_delete (filt) ;
      filt = 0 ;
    }

    /* release image data */
    if (fdata) {
      free (fdata) ;
      fdata = 0 ;
    }

    /* release image data */
    if (data) {
      free (data) ;
      data = 0 ;
    }

    /* close files */
    if (in) {
      fclose (in) ;
      in = 0 ;
    }

    vl_file_meta_close (&out) ;
    vl_file_meta_close (&frm) ;
    vl_file_meta_close (&dsc) ;
    vl_file_meta_close (&met) ;
    vl_file_meta_close (&gss) ;
    vl_file_meta_close (&ifr) ;

    /* if bad print error message */
    if (err) {
      fprintf
        (stderr,
         "sift: err: %s (%d)\n",
         err_msg,
         err) ;
      exit_code = 1 ;
    }
  }

  /* quit */
  return exit_code ;
}