void test_collapsing_find_simple(CuTest* tc) {
label_t equivs[] = {0, 0, 1, 2};
/* 0 1 2 3 */
label_t minlabel = collapsing_find_minlabel(3, equivs);
CuAssertIntEquals(tc, minlabel, 0);
CuAssertIntEquals(tc, equivs[0], 0);
CuAssertIntEquals(tc, equivs[1], 0);
CuAssertIntEquals(tc, equivs[2], 0);
CuAssertIntEquals(tc, equivs[3], 0);
}
static dimage_label_t relabel_image(il* on_pixels,
int maxlabel,
dimage_label_t* equivs,
int* object) {
int i;
dimage_label_t maxcontiguouslabel = 0;
dimage_label_t *number;
number = malloc(sizeof(dimage_label_t) * maxlabel);
assert(number);
for (i = 0; i < maxlabel; i++)
number[i] = LABEL_MAX;
for (i=0; i<il_size(on_pixels); i++) {
int onpix;
int minlabel;
onpix = il_get(on_pixels, i);
minlabel = collapsing_find_minlabel(object[onpix], equivs);
if (number[minlabel] == LABEL_MAX)
number[minlabel] = maxcontiguouslabel++;
object[onpix] = number[minlabel];
}
free(number);
return maxcontiguouslabel;
}
int DFIND2(const IMGTYPE* image,
int nx,
int ny,
int* object,
int* pnobjects) {
int ix, iy, i;
int maxgroups = initial_max_groups;
label_t *equivs = malloc(sizeof(label_t) * maxgroups);
int maxlabel = 0;
/* Keep track of 'on' pixels to avoid later rescanning */
il* on_pixels = il_new(256);
/* Find blobs and track equivalences */
for (iy = 0; iy < ny; iy++) {
for (ix = 0; ix < nx; ix++) {
int thislabel, thislabelmin;
object[nx*iy+ix] = -1;
if (!image[nx*iy+ix])
continue;
/* Store location of each 'on' pixel. */
il_append(on_pixels, nx * iy + ix);
/* If the pixel to the left [exists and] is on, this pixel
joins its group. */
if (ix && image[nx*iy+ix-1]) {
/* Old group */
object[nx*iy+ix] = object[nx*iy+ix-1];
} else {
/* New blob */
// FIXME this part should become uf_new_group()
if (maxlabel >= maxgroups) {
maxgroups *= 2;
equivs = realloc(equivs, sizeof(label_t) * maxgroups);
assert(equivs);
}
object[nx*iy+ix] = maxlabel;
equivs[maxlabel] = maxlabel;
maxlabel++;
if (maxlabel == LABEL_MAX) {
logverb("Ran out of labels. Relabelling...\n");
maxlabel = relabel_image(on_pixels, maxlabel, equivs, object);
logverb("After relabelling, we need %i labels\n", maxlabel);
if (maxlabel == LABEL_MAX) {
ERROR("Ran out of labels.");
exit(-1);
}
}
}
thislabel = object[nx*iy + ix];
/* Compute minimum equivalence label for this pixel */
thislabelmin = collapsing_find_minlabel(thislabel, equivs);
if (iy == 0)
continue;
/* Check three pixels above this one which are 'neighbours' */
for (i = MAX(0, ix - 1); i <= MIN(ix + 1, nx - 1); i++) {
if (image[nx*(iy-1)+i]) {
int otherlabel = object[nx*(iy-1) + i];
/* Find min of the other */
int otherlabelmin = collapsing_find_minlabel(otherlabel, equivs);
/* Merge groups if necessary */
if (thislabelmin != otherlabelmin) {
int oldlabelmin = MAX(thislabelmin, otherlabelmin);
int newlabelmin = MIN(thislabelmin, otherlabelmin);
thislabelmin = newlabelmin;
equivs[oldlabelmin] = newlabelmin;
equivs[thislabel] = newlabelmin;
/* Update other pixel too */
object[nx*(iy-1) + i] = newlabelmin;
}
}
}
object[nx*iy + ix] = thislabelmin;
}
}
/* Re-label the groups before returning */
maxlabel = relabel_image(on_pixels, maxlabel, equivs, object);
//logverb("After final relabelling, %i labels were used.\n", maxlabel);
if (pnobjects)
*pnobjects = maxlabel;
free(equivs);
il_free(on_pixels);
return 1;
}
