linknew.c

The salience distance transform incorporates edge strength information into the distance transform.

    for (loop1 = 0; loop1 < height; loop1++)
        for (loop2 = 0; loop2 < width; loop2++)
            if (image[loop1][loop2] != BLACK)
                number++;
	/***
    printf("number: %d\n", number);
	***/
}


remove_isolated()
{
    int loop1, loop2;
    unsigned char i1, i2, i3, i4, i6, i7, i8, i9;
    long number;

	/***
    printf("removing isolated points...\n");
	***/
    number = 0;
    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;
                    number++;
                }
            }
	/***
    printf("number of points removed: %d\n", number);
	***/
}


link_open(option)
int option;
/*
 * option = 0  write list to disk option = 1  write significant lines to disk
 */

{
    int loop1, loop2, loop3;
    unsigned char i1, i2, i3, i4, i6, i7, i8, i9;
    int xp, yp;
    int end_of_line;

    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 = 0;
                i2 = 0;
                i3 = 0;
                i4 = 0;
                i6 = 0;
                i7 = 0;
                i8 = 0;
                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)
                    i6 = 1;
                if (image[loop1 - 1][loop2 + 1] != BLACK)
                    i7 = 1;
                if (image[loop1][loop2 + 1] != BLACK)
                    i8 = 1;
                if (image[loop1 + 1][loop2 + 1] != BLACK)
                    i9 = 1;
                if ((i1 + i2 + i3 + i4 + i6 + i7 + i8 + i9) == 1) {
                    weight = 0;
                    index = 0;
                    list_no++;
                    end_of_line = FALSE;
                    /* track to end of line */
                    xp = loop2;
                    yp = loop1;
                    do {
                        weight = weight + (unsigned char) image[yp][xp];
                        index++;
                        xpix[index] = (float) xp;
                        ypix[index] = (float) yp / aspect_ratio;
                        image[yp][xp] = BLACK;
                        /* goto next pixel if an edge
                           pixel */
                        i1 = image[yp - 1][xp - 1];
                        i2 = image[yp][xp - 1];
                        i3 = image[yp + 1][xp - 1];
                        i4 = image[yp - 1][xp];
                        i6 = image[yp + 1][xp];
                        i7 = image[yp - 1][xp + 1];
                        i8 = image[yp][xp + 1];
                        i9 = image[yp + 1][xp + 1];
                        if (i1 != BLACK) {
                            xp--;
                            yp--;
                        }
                        else if (i2 != BLACK) {
                            xp--;
                        }
                        else if (i3 != BLACK) {
                            yp++;
                            xp--;
                        }
                        else if (i4 != BLACK) {
                            yp--;
                        }
                        else if (i6 != BLACK) {
                            yp++;
                        }
                        else if (i7 != BLACK) {
                            yp--;
                            xp++;
                        }
                        else if (i8 != BLACK) {
                            xp++;
                        }
                        else if (i9 != BLACK) {
                            xp++;
                            yp++;
                        }
                        else
                            end_of_line = TRUE;
                    } while (end_of_line == FALSE);

                    if (lowe) weight /= (float)index;

                    if (option == 1) {
                        /* only write if significant */
                        if (weight < 0)
                            printf("weight: %f\n",weight);
                        if (weight > thresh_sig) {
                            if (closed_only == FALSE) {
                                no_lists_written++;
                                /*
                                   printf("writing list %d weight %f\n",
                                           list_no,weight);
                                */
                                if (flag == TRUE)
                                    fprintf(fp_out, "  -1    0\n");
                                flag = TRUE;
                                fprintf(fp_out, "list:  %d\n", list_no);
                                if (floating_point == TRUE) {
                                    for (loop3 = 1; loop3 <= index; loop3++)
                                        fprintf(fp_out, "%f %f\n",
                                            xpix[loop3], ypix[loop3]);
                                }
                                else {
                                    for (loop3 = 1; loop3 <= index; loop3++)
                                        fprintf(fp_out, "%4.0f %4.0f\n",
                                            xpix[loop3], ypix[loop3]);
                                }
                            }
                        }
                    }
                    else {    /* option = 0 */
                        /* write all lines */
                        if (closed_only == FALSE) {
                            no_lists_written++;
                            /*
                                printf("writing list %d  weight %f\n",
                                list_no,weight);
                            */
                            if (flag == TRUE)
                                fprintf(fp_out, "  -1    0\n");
                            flag = TRUE;
                            fprintf(fp_out, "list:   %d\n", list_no);
                            if (floating_point == TRUE) {
                                for (loop3 = 1; loop3 <= index; loop3++)
                                    fprintf(fp_out, "%f %f\n",
                                        xpix[loop3], ypix[loop3]);
                            }
                            else {
                                for (loop3 = 1; loop3 <= index; loop3++)
                                    fprintf(fp_out, "%4.0f %4.0f\n",
                                        xpix[loop3], ypix[loop3]);
                            }
                        }
                    }
                }
            }
        }
}


link_closed(option)
int option;
/*
 * option = 0  write list to disk option = 1  write significant lines to disk
 */
{
    int loop1, loop2, loop3;
    unsigned char i1, i2, i3, i4, i6, i7, i8, i9;
    int xp, yp;
    int end_of_line;

    for (loop1 = 0; loop1 < height; loop1++)    /* for each row */
        for (loop2 = 0; loop2 < width; loop2++) {    /* for each column */
            /* find any remaining pixel */
            if (image[loop1][loop2] != BLACK) {
                /* at beginning of a line */
                weight = 0;
                index = 0;
                list_no++;
                end_of_line = FALSE;
                /* track to end of line */
                xp = loop2;
                yp = loop1;
                do {
                    index++;
                    xpix[index] = xp;
                    ypix[index] = round(yp / aspect_ratio);
                    weight = weight + (unsigned char) image[yp][xp];
                    image[yp][xp] = BLACK;
                    /* goto next edge pixel */
                    i1 = image[yp - 1][xp - 1];
                    i2 = image[yp][xp - 1];
                    i3 = image[yp + 1][xp - 1];
                    i4 = image[yp - 1][xp];
                    i6 = image[yp + 1][xp];
                    i7 = image[yp - 1][xp + 1];
                    i8 = image[yp][xp + 1];
                    i9 = image[yp + 1][xp + 1];
                    if (i1 != BLACK) {
                        xp--;
                        yp--;
                    }
                    else if (i2 != BLACK) {
                        xp--;
                    }
                    else if (i3 != BLACK) {
                        yp++;
                        xp--;
                    }
                    else if (i4 != BLACK) {
                        yp--;
                    }
                    else if (i6 != BLACK) {
                        yp++;
                    }
                    else if (i7 != BLACK) {
                        yp--;
                        xp++;
                    }
                    else if (i8 != BLACK) {
                        xp++;
                    }
                    else if (i9 != BLACK) {
                        xp++;
                        yp++;
                    }
                    else
                        end_of_line = TRUE;
                } while (end_of_line != TRUE);

                if (lowe) weight /= (float)index;

                if (option == 1) {
                    /* only write if signoficant */
                    if (weight < 0)
                        printf("weight: %f\n",weight);
                    if (weight > thresh_sig) {
                        no_lists_written++;
                        /* printf("writing list %d weight %f\n",
                            list_no,weight);
                        */
                        if (flag == TRUE)
                            fprintf(fp_out, "  -1    0\n");
                        flag = TRUE;
                        fprintf(fp_out, "list:   %d\n", list_no);
                        if (floating_point == TRUE) {
                            for (loop3 = 1; loop3 <= index; loop3++)
                                fprintf(fp_out, "%f %f\n",
                                    xpix[loop3], ypix[loop3]);
                        }
                        else {
                            for (loop3 = 1; loop3 <= index; loop3++)
                                fprintf(fp_out, "%4.0f %4.0f\n",
                                    xpix[loop3], ypix[loop3]);
                        }
                    }
                }
                else {    /* option = 0 */
                    /* write all lines */
                    no_lists_written++;
                    /* printf("writing list %d weight %f\n",
                        list_no,weight); */
                    if (flag == TRUE)
                        fprintf(fp_out, "  -1    0\n");
                    flag = TRUE;
                    fprintf(fp_out, "list:   %d\n", list_no);
                    if (floating_point == TRUE) {
                        for (loop3 = 1; loop3 <= index; loop3++)
                            fprintf(fp_out, "%f %f\n",
                                xpix[loop3], ypix[loop3]);
                    }
                    else {
                        for (loop3 = 1; loop3 <= index; loop3++)
                            fprintf(fp_out, "%4.0f %4.0f\n",
                                xpix[loop3], ypix[loop3]);
                    }
                }
            }
        }
}

int
round(x)
float x;
{
    return floor(x + 0.5);
}