link_dynamic.c

自适应的目标识别算法

/*
 * 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
 * [e-mail]
 */

#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 < width; loop2++) {    /* for each column x */
            /* find pixel at end of line */
            if (image[loop1][loop2] != BLACK) {
                i1 = i2 = i3 = i4 = i6 = i7 = i8 = i9 = 0;
                if (image[loop1 - 1][loop2 - 1] != BLACK)
                    i1 = 1;
                if (image[loop1][loop2 - 1] != BLACK)
                    i2 = 1;
                if (image[loop1 + 1][loop2 - 1] != BLACK)
                    i3 = 1;
                if (image[loop1 - 1][loop2] != BLACK)
                    i4 = 1;
                if (image[loop1 + 1][loop2] != BLACK)