/* * computes salience distance transform * distance weighted by: *        edge magnitude *        pixel list length * * (serial) chamfer algorithm used, either 3-4 or 5-7-11 * * Paul Rosin * August 1994 */#include <stdio.h>#include <math.h>#ifndef FALSE# define FALSE 0# define TRUE (!FALSE)#endif#define K 1#define MAX_SIZE 1024#include "pgmio.h"#define CHAMFER34   0#define CHAMFER5711 1#define ALGORITHM CHAMFER34#if ALGORITHM == CHAMFER34# define MASK_SIZE 5  int x_offset[MASK_SIZE] = { -1,  0,  1, -1,  0 };  int y_offset[MASK_SIZE] = { -1, -1, -1,  0,  0 };  int i_offset[MASK_SIZE] = {  4,  3,  4,  3,  0 };#elif ALGORITHM == CHAMFER5711# define MASK_SIZE 9  int x_offset[MASK_SIZE] = { -1,  1, -2, -1,  0,  1,  2, -1,  0 };  int y_offset[MASK_SIZE] = { -2, -2, -1, -1, -1, -1, -1,  0,  0 };  int i_offset[MASK_SIZE] = { 11, 11, 11,  7,  5,  7, 11,  5,  0 };#endif#define MAX_PIXELS 50000int x[MAX_PIXELS],y[MAX_PIXELS];int no_pixels;unsigned char tmp[MAX_SIZE][MAX_SIZE];int image_dist[MAX_SIZE][MAX_SIZE];unsigned char image_mag[MAX_SIZE][MAX_SIZE];double image_measure[MAX_SIZE][MAX_SIZE];int image_length[MAX_SIZE][MAX_SIZE];int height,width,depth;int max_iter = 10;    /* usually terminates after 4 or 5 iterations anyway */main(argc,argv)int argc;char *argv[];{    int i,j,x,y;    int change;    int d[MASK_SIZE],m[MASK_SIZE],l[MASK_SIZE];    double measure,min_measure,prev_measure;    char *binary_file,*outfile,*edge_file,*pixel_file;    double max_val;    int min_loc;    int xn,yn;    FILE *fp;    char file_type[50];    int endoffile;    pixel_file = binary_file = outfile = edge_file = NULL;    /* parse command line */    for(i = 1; i < argc; i++) {        if (argv[i][0] == '-') {            switch(argv[i][1]) {                case 'b':                    i++;                    binary_file = argv[i];                    break;                case 'e':                    i++;                    edge_file = argv[i];                    break;                case 'o':                    i++;                    outfile = argv[i];                    break;                case 'p':                    i++;                    pixel_file = argv[i];                    break;                case 'n':                    i++;                    max_iter = atoi(argv[i]);                    printf("number of iterations: %d\n",max_iter);                    break;                default:                    printf("unknown option %s\n",argv[i]);                    options(argv[0]);            }        }        else {            printf("unknown option %s\n",argv[i]);            options(argv[0]);        }    }    if (outfile == NULL || edge_file == NULL || pixel_file == NULL)        options(argv[0]);    /* read and pixel lists and store lengths */    if ((fp=fopen(pixel_file,"r")) == NULL) {        printf("cant open pixel file: %s\n",pixel_file);        exit(-1);    }    /* read magic word for format of file */    fscanf(fp,"%s\n",file_type);    j = strcmp(file_type,"pixel");    if (j != 0){        printf("not link data file - aborting\n");        exit();    }    for (j = 0; j < height; j++)        for (i = 0; i < width; i++)            image_length[j][i] = 0;    do {        read_link_data(fp,&endoffile);        store_length();    } while (!endoffile);    fclose(fp);#if (ALGORITHM == CHAMFER34)    printf("performing chamfer3-4\n");#elif (ALGORITHM == CHAMFER5711)    printf("performing chamfer5-7-11\n");#endif    read_pgm(image_mag,edge_file,&width,&height,&depth);    if (binary_file != NULL) {        read_pgm(tmp,binary_file,&width,&height,&depth);        /* copy into integer array */        for (y = 0; y < height; y++)            for (x = 0; x < width; x++)                image_dist[x][y] = tmp[x][y];    }    else {        /* threshold magnitude image */        for (y = 0; y < height; y++)            for (x = 0; x < width; x++)                if ((unsigned int)image_mag[x][y] > 0)                    image_dist[x][y] = 0;                else                    image_dist[x][y] = 255;    }    /* propagate distance etc */    j = 0;    do {        j++;        printf("iteration %d\n",j);        change = FALSE;        /* forward pass */        for (y = 1; y < height-1; y++) {            for (x = 1; x < width-1; x++) {                prev_measure = (double) (image_dist[x][y]+K) /                               (double) (((unsigned int)image_mag[x][y]+K) *                                          (image_length[x][y]+K));                for (i = 0; i < MASK_SIZE; i++) {                    xn = x + x_offset[i]; yn = y + y_offset[i];                    d[i] = image_dist[xn][yn] + i_offset[i];                    m[i] = (unsigned int)image_mag[xn][yn];                    l[i] = image_length[xn][yn];                }                min_loc = 0;                min_measure = (double) (d[0]+K) /                              (double) ((m[0]+K) * (l[0]+K));                for (i = 1; i < MASK_SIZE; i++) {                    measure = (double) (d[i]+K) / (double) ((m[i]+K) * (l[i]+K));                    if (measure < min_measure) {                        min_measure = measure;                        min_loc = i;                    }                }                image_dist[x][y] = d[min_loc];                image_mag[x][y] = m[min_loc];                image_length[x][y] = l[min_loc];                if (prev_measure != min_measure)                    change = TRUE;            }        }        /* backward pass */        for (y = height-2; y >= 1; y--) {            for (x = width-2; x >= 1; x--) {                prev_measure = (double) (image_dist[x][y]+K) /                               (double) (((unsigned int)image_mag[x][y]+K) *                                          (image_length[x][y]+K));                for (i = 0; i < MASK_SIZE; i++) {                    xn = x - x_offset[i]; yn = y - y_offset[i];                    d[i] = image_dist[xn][yn] + i_offset[i];                    m[i] = (unsigned int)image_mag[xn][yn];                    l[i] = image_length[xn][yn];                }                min_loc = 0;                min_measure = (double) (d[0]+K) /                              (double) ((m[0]+K) * (l[0]+K));                for (i = 1; i < MASK_SIZE; i++) {                    measure = (double) (d[i]+K) / (double) ((m[i]+K) * (l[i]+K));                    if (measure < min_measure) {                        min_measure = measure;                        min_loc = i;                    }                }                image_dist[x][y] = d[min_loc];                image_mag[x][y] = m[min_loc];                image_length[x][y] = l[min_loc];                if (prev_measure != min_measure)                    change = TRUE;            }        }    } while (change && j < max_iter);    /* calculate measure values */    for (y = 1; y < height-1; y++) {        for (x = 1; x < width-1; x++) {            image_measure[x][y] = (double) (image_dist[x][y]+K) /                                 ((double) ((unsigned int)image_mag[x][y]+K) *                                            (image_length[x][y]+K));        }    }    /* rescale */    max_val = image_measure[1][1];    for (y = 1; y < height-1; y++)        for (x = 1; x < width-1; x++)            if (image_measure[x][y] > max_val)                max_val = image_measure[x][y];    for (y = 1; y < height-1; y++)        for (x = 1; x < width-1; x++)            tmp[x][y] = (unsigned int)(image_measure[x][y] * 255 / max_val);    /* reset borders */    for (y = 0; y < height; y++)        tmp[0][y] = tmp[width-1][y] = 255;    for (x = 0; x < width; x++)        tmp[x][0] = tmp[x][height-1] = 255;    write_pgm(tmp,outfile,width,height);}store_length(){    int i;    for (i = 0; i < no_pixels; i++)        image_length[x[i]][y[i]] = no_pixels;}read_link_data(fp,endoffile)FILE *fp;int *endoffile;{    char dumstring[50];    int j;    fscanf(fp,"%s %d\n",dumstring,&j);    j = -1;    do{       j++;       fscanf(fp,"%d %d\n",&x[j],&y[j]);    } while(x[j] != -1);    *endoffile = (y[j] == -1);    no_pixels = j;}options(progname)char *progname;{    printf("usage: %s [options]\n",progname);    printf("     -b file    binary edge map (optional)\n");    printf("     -e file    edge magnitude map\n");    printf("     -o file    output distance map\n");    printf("     -p file    pixel lists\n");    printf("     -n int     maximum number of iterations (default: %d)\n",max_iter);    exit(-1);}