/* file: mfilt.c G. Moody 27 June 1993
Last revised: 24 April 2020
-------------------------------------------------------------------------------
mfilt: General-purpose median filter for database records
Copyright (C) 1993-2006 George B. Moody
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, see <http://www.gnu.org/licenses/>.
You may contact the author by e-mail (wfdb@physionet.org) or postal mail
(MIT Room E25-505A, Cambridge, MA 02139 USA). For updates to this software,
please visit PhysioNet (http://www.physionet.org/).
_______________________________________________________________________________
*/
#include <stdio.h>
#include <wfdb/wfdb.h>
char *pname; /* name by which this program was invoked */
char *nrec; /* name of record to be created */
int flen; /* filter length */
int median; /* offset of median element within vtemp array after sorting */
int nsig; /* number of signals to be filtered */
int **vin; /* pointers to input vectors */
int *vtemp; /* temporary array for calculating medians */
int *vout; /* output vector */
WFDB_Time from = 0L; /* first sample to be processed */
WFDB_Time to = 0L; /* (if > 0) sample following last sample to be processed */
WFDB_Time spm; /* samples per minute */
WFDB_Time tt; /* time to print next progress indicator */
char *prog_name();
void help(), init(), memerr();
int icmp(x, y)
int *x, *y;
{
return (*y - *x);
}
main(argc, argv)
int argc;
char *argv[];
{
int i = 0, j, s;
WFDB_Time t;
init(argc, argv); /* read and interpret command line */
if (from < median) { /* preload array with copies of sample 0 */
(void)getvec(vin[0]);
for (i = 1; i <= median - from; i++)
for (s = 0; s < nsig; s++)
vin[i][s] = vin[0][s];
}
else if (isigsettime(from - median) < 0)
exit(2);
for ( ; i < flen; i++)
(void)getvec(vin[i]);
for (t = from; to <= 0L || t < to; t++) {
for (s = 0; s < nsig; s++) {
for (j = 0; j < flen; j++)
vtemp[j] = vin[j][s];
qsort((char *)vtemp, flen, sizeof(int), icmp);
if (flen & 1) /* odd length -- median is middle element */
vout[s] = vtemp[median];
else /* even length -- median is avg. of two middle elements */
vout[s] = (vtemp[median] + vtemp[median-1])/2;
}
if (++i >= flen)
i = 0;
if (putvec(vout) < 0 || getvec(vin[i]) < 0)
break;
if (t > tt) {
(void)fprintf(stderr, ".");
tt += spm;
}
}
if (to <= 0L) to = t + flen - median;
for (; t < to; t++)
(void)putvec(vout); /* pad output to length of input record */
(void)fprintf(stderr, "\n");
if (nrec) (void)newheader(nrec);
wfdbquit();
exit(0); /*NOTREACHED*/
}
void init(argc, argv)
int argc;
char *argv[];
{
char *irec = "16", *ofname, *orec = "16", *p;
int format, i;
static int gvmode = 0;
static WFDB_Siginfo *si, *so;
pname = prog_name(argv[0]);
for (i = 1; i < argc; i++) {
if (*argv[i] == '-') switch (*(argv[i]+1)) {
case 'f': /* starting time */
if (++i >= argc) {
(void)fprintf(stderr, "%s: time must follow -f\n", pname);
exit(1);
}
from = i;
break;
case 'h': /* help requested */
help();
exit(0);
break;
case 'H': /* operate in WFDB_HIGHRES mode */
gvmode = WFDB_HIGHRES;
break;
case 'i': /* input record name */
if (++i >= argc) {
(void)fprintf(stderr, "%s: record name must follow -i\n",
pname);
exit(1);
}
irec = argv[i];
break;
case 'l': /* filter length */
if (++i >= argc || (flen = atoi(argv[i])) < 1) {
(void)fprintf(stderr,
"%s: filter length (> 0) must follow -l\n",
pname);
exit(1);
}
break;
case 'n': /* new record name */
if (++i >= argc) {
(void)fprintf(stderr, "%s: record name must follow -n\n",
pname);
exit(1);
}
nrec = argv[i];
break;
case 'o': /* output record name */
if (++i >= argc) {
(void)fprintf(stderr, "%s: record name must follow -o\n",
pname);
exit(1);
}
orec = argv[i];
break;
case 't': /* end time */
if (++i >= argc) {
(void)fprintf(stderr, "%s: time must follow -t\n", pname);
exit(1);
}
to = i;
break;
default:
(void)fprintf(stderr, "%s: unrecognized option %s\n", pname,
argv[i]);
exit(1);
}
else {
(void)fprintf(stderr, "%s: unrecognized argument %s\n", pname,
argv[i]);
exit(1);
}
}
if (flen < 1) {
help();
exit(1);
}
median = flen/2;
if (gvmode == 0 && (p = getenv("WFDBGVMODE")))
gvmode = atoi(p);
setgvmode(gvmode|WFDB_GVPAD);
if ((nsig = isigopen(irec, NULL, 0)) <= 0)
exit(2);
if ((si = (WFDB_Siginfo *)malloc(nsig * sizeof(WFDB_Siginfo))) == NULL ||
(so = (WFDB_Siginfo *)malloc(nsig * sizeof(WFDB_Siginfo))) == NULL ||
(vtemp = (int *)calloc((unsigned)flen, sizeof(int))) == NULL ||
(vin = (int **)calloc((unsigned)flen, sizeof(int *))) == NULL ||
(vout = (int *)malloc(nsig * sizeof(int))) == NULL)
memerr();
for (i = 0; i < flen; i++)
if ((vin[i] = (int *)calloc((unsigned)nsig, sizeof(int))) == NULL)
memerr();
if (isigopen(irec, si, (unsigned)nsig) != nsig)
exit(2);
if (nrec) {
if ((ofname = (char *)malloc(strlen(nrec)+5)) == NULL)
memerr();
(void)sprintf(ofname, "%s.dat", nrec);
format = si[0].fmt;
for (i = 0; i < nsig; i++) {
si[i].fname = ofname;
si[i].fmt = format;
si[i].spf = 1;
}
if (osigfopen(si, (unsigned)nsig) < nsig)
exit(2);
setsampfreq(sampfreq(NULL));
}
else if (osigopen(orec, so, (unsigned)nsig) != nsig)
exit(2);
if (from > 0L) {
if ((from = strtim(argv[from])) < 0L) from = -from;
}
if (to > 0L) {
if ((to = strtim(argv[to])) < 0L) to = -to;
if (to > 0L && to <= from) {
(void)fprintf(stderr, "%s: improper interval specified\n", pname);
exit(1);
}
}
spm = strtim("1:0"); /* samples per minute */
tt = from + spm; /* time to print next progress indicator */
}
void memerr()
{
(void)fprintf(stderr, "%s: insufficient memory\n", pname);
exit(2);
}
char *prog_name(s)
char *s;
{
char *p = s + strlen(s);
#ifdef MSDOS
while (p >= s && *p != '\\' && *p != ':') {
if (*p == '.')
*p = '\0'; /* strip off extension */
if ('A' <= *p && *p <= 'Z')
*p += 'a' - 'A'; /* convert to lower case */
p--;
}
#else
while (p >= s && *p != '/')
p--;
#endif
return (p+1);
}
static char *help_strings[] = {
"usage: %s -l N [OPTIONS ...]\n",
"where N is the filter length (output is median of N samples in each signal),",
"and OPTIONS may include:",
" -f TIME begin at specified time",
" -h print this usage summary",
" -H read multifrequency signals in high resolution mode",
" -i IREC read signals from record IREC (default: 16)",
" -n NREC create a header file, using record name NREC and signal",
" specifications from IREC",
" -o OREC produce output signal file(s) as specified by the header file",
" for record OREC (default: 16)",
" -t TIME stop at specified time",
NULL
};
void help()
{
int i;
(void)fprintf(stderr, help_strings[0], pname);
for (i = 1; help_strings[i] != NULL; i++)
(void)fprintf(stderr, "%s\n", help_strings[i]);
}