/*
* link_dynamic.c
*
* extracts lists of edge pixels from an image
* automatically determines a threshold value to reject poor edge lists
*
* two threshold methods:
* 1/ linear decision rule
* 2/ 3*sigma/length decision rule
*
* usage: run the program twice
* 1st time: edge list statistics are generated
* then calculate median information, using:
* 1/ median4 or
* 2/ estimate_noise
* 2nd time: edge lists above threshold are output
* it's much easier to use the shell scripts provided!
*
* original program (based on "linknew.c" written by Geoff West):
*
* partly described in:
* Svetha Venkatesh & Paul L. Rosin,
* Dynamic threshold determination by local and global edge evaluation,
* Graphical Models & Image Processing,
* Vol. 75, No. 2, pp. 146-160, 1995.
*
* Paul Rosin & Svetha Venkatesh
* Curtin University
* Perth, Western Australia
* February 1993
*
* ------------------------------------------------------------------
*
* updated with non-linear decision rule:
* Paul Rosin
* Joint Research Centre
* Ispra, Italy
* December 1994
* paul.rosin@jrc.it
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "malloc_image.h"
#ifndef FALSE
# define FALSE 0
# define TRUE (!FALSE)
#endif
#define MAX_PIX 10000
#define BLACK 0
#define WHITE 255
#define WIDTH 512
#define HEIGHT 512
#define OLD_INFO 0 /* output all edge list information */
#define OLD_THRESH 1 /* output edge lists above threshold */
#define NEW_INFO 2 /* output all edge list information - new format */
#define NEW_THRESH 3 /* output edge lists above threshold - new version */
int list_no;
float xpix[MAX_PIX],ypix[MAX_PIX];
int Index;
long weight;
int flag;
int no_lists_written;
float aspect_ratio; /* defined as y/x and divide y value by this */
int closed_only;
int floating_point;
FILE *fp_out;
unsigned char **image;
int height,width;
char *file_in=NULL,*file_out=NULL;
int round();
FILE *fp_in;
/* additional variables added for automatic thresholding */
float xx1,yy1,xx2,yy2;
float slope,intercept;
/* new additional variables added for automatic thresholding */
float med_mag,dev;
float fact = 2;
main(argc,argv)
int argc;
char *argv[];
{
int i;
int option = OLD_INFO;
closed_only = FALSE;
aspect_ratio = 1.0;
floating_point = FALSE;
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-') {
switch(argv[i][1]) {
case 'i':
i++;
file_in = argv[i];
break;
case 'o':
i++;
file_out = argv[i];
break;
case 'n':
option = NEW_INFO;
break;
case 'c':
closed_only = TRUE;
break;
case 'a':
i++;
aspect_ratio = atof(argv[i]);
printf("aspect ratio is: %f\n",aspect_ratio);
break;
case 'd':
i++;
xx1 = atof(argv[i]);
i++;
yy1 = atof(argv[i]);
i++;
xx2 = atof(argv[i]);
i++;
yy2 = atof(argv[i]);
option = OLD_THRESH;
slope = (float)(yy2 - yy1) / (float)(xx2 -xx1);
intercept = yy1;
break;
case 'D':
i++;
med_mag = atof(argv[i]);
i++;
dev = atof(argv[i]);
option = NEW_THRESH;
break;
case 'F':
i++;
fact = atof(argv[i]);
break;
case 'f':
floating_point = TRUE;
break;
default:
fprintf(stderr,"unknown option %s\n",argv[i]);
options(argv[0]);
}
}
else {
fprintf(stderr,"unknown option %s\n",argv[i]);
options(argv[0]);
}
}
if ((file_in == NULL) || (file_out == NULL)) {
fprintf(stderr,"ERROR: need filenames\n");
options(argv[0]);
}
link_and_save(option);
}
link_and_save(option)
int option;
{
flag = FALSE; /* at start only - no lists */
no_lists_written = 0;
read_pgm_header(file_in,&width,&height);
image = malloc_char_image(width,height);
read_image_body(image,width,height);
/* clean up image, make all object 8 connected */
clean();
/* remove isolated points - of no interest to us here */
remove_isolated();
if ((fp_out = fopen(file_out, "w")) == NULL) {
printf("file %s cannot be created - aborting\n", file_out);
exit(-1);
}
/* put magic name at top of file */
if (option == OLD_INFO) {
fprintf(fp_out,"super\nlist:\n");
}
else if ((option == OLD_THRESH) || (option == NEW_THRESH)) {
if (floating_point == TRUE)
fprintf(fp_out, "pixel_float\n");
else
fprintf(fp_out, "pixel\n");
}
/* link open edges */
list_no = 0;
link_open(option);
/* remove isolated points - of no interest to us here */
remove_isolated();
/* link closed edges */
link_closed(option);
/* remove isolated points - of no interest to us here */
remove_isolated();
if (option == OLD_INFO)
fprintf(fp_out,"endl:\nendf:\n");
else if ((option == OLD_THRESH) || (option == NEW_THRESH))
fprintf(fp_out, "-1 -1\n");
fclose(fp_out);
}
clean()
{
int loop1, loop2;
unsigned char i1, i2, i3, i4;
/* clear border */
for (loop1 = 0; loop1 < height; loop1++)
image[loop1][0] = image[loop1][width - 1] = BLACK;
for (loop1 = 0; loop1 < width; loop1++)
image[0][loop1] = image[height - 1][loop1] = BLACK;
for (loop1 = 1; loop1 < height - 1; loop1++)
for (loop2 = 1; loop2 < width - 1; loop2++)
if (image[loop1][loop2] != BLACK) {
i1 = image[loop1 - 1][loop2];
i2 = image[loop1][loop2 - 1];
i3 = image[loop1 + 1][loop2];
i4 = image[loop1][loop2 + 1];
if ((i1 != BLACK) && (i2 != BLACK))
image[loop1][loop2] = BLACK;
else if ((i2 != BLACK) && (i3 != BLACK))
image[loop1][loop2] = BLACK;
else if ((i3 != BLACK) && (i4 != BLACK))
image[loop1][loop2] = BLACK;
else if ((i4 != BLACK) && (i1 != BLACK))
image[loop1][loop2] = BLACK;
}
}
remove_isolated()
{
int loop1,loop2;
unsigned char i1,i2,i3,i4,i6,i7,i8,i9;
for (loop1 = 1; loop1 < height - 1; loop1++)
for (loop2 = 1; loop2 < width - 1; loop2++)
if (image[loop1][loop2] != BLACK) {
i1 = image[loop1 - 1][loop2 - 1];
i2 = image[loop1][loop2 - 1];
i3 = image[loop1 + 1][loop2 - 1];
i4 = image[loop1 - 1][loop2];
i6 = image[loop1 + 1][loop2];
i7 = image[loop1 - 1][loop2 + 1];
i8 = image[loop1][loop2 + 1];
i9 = image[loop1 + 1][loop2 + 1];
if ((i1 + i2 + i3 + i4 + i6 + i7 + i8 + i9) == (8 * BLACK)) {
image[loop1][loop2] = BLACK;
}
}
}
link_open(option)
int option;
{
int loop1,loop2,loop3;
unsigned char i1,i2,i3,i4,i6,i7,i8,i9;
int xp,yp;
int end_of_line;
int ok;
for (loop1 = 0; loop1 < height; loop1++) /* for each row y */
for (loop2 = 0; loop2 < wi
