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Chapter 3 ■ Digital Morphology 95

void dil_apply (IMAGE im, SE p, int ii, int jj, IMAGE res)
{
int i,j, is,js, ie, je, k;
/* Find start and end pixel in IM */
is = ii - p->oi; js = jj - p->oj; ie = is + p->nr; je = js + p->nc;

/* Place SE over the image from (is,js) to (ie,je). Set pixels
in RES if the corresponding SE pixel is 1; else do nothing. */
for (i=is; i<ie; i++)
for (j=js; j<je; j++)
{
if (range(im,i,j))
{
k = (p->data[i-is][j-js] == 1);
if (k>=0) res->data[i][j] |= k;
} } }
int bin_dilate (IMAGE im, SE p)
{
IMAGE tmp;
int i,j;

/* Source image empty? */
if (im==0)
{
printf ( ˝ Bad image in BIN_DILATE\n˝);
return 0;
}
/* Create a result image */
tmp = newimage (im->info->nr, im->info->nc);
if (tmp == 0)
{
printf ( ˝ Out of memory in BIN_DILATE.\n˝);
return 0;
}
for (i=0; i<tmp->info->nr; i++)
for (j=0; j<tmp->info->nc; j++)
tmp->data[i][j] = 0;
/* Apply the SE to each black pixel of the input */
for (i=0; i<im->info->nr; i++)
for (j=0; j<im->info->nc; j++)
if (im->data[i][j] == WHITE)
dil_apply (im, p, i, j, tmp);
/* Copy result over the input */
for (i=0; i<im->info->nr; i++)
for (j=0; j<im->info->nc; j++)
im->data[i][j] = tmp->data[i][j];
/* Free the result image - it was a temp */
freeimage (tmp);
return 1;
}

Figure 3.6: C source code for the dilation of a binary image by a binary structuring element.