/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
- This software is distributed in the hope that it will be
- useful, but with NO WARRANTY OF ANY KIND.
- No author or distributor accepts responsibility to anyone for the
- consequences of using this software, or for whether it serves any
- particular purpose or works at all, unless he or she says so in
- writing. Everyone is granted permission to copy, modify and
- redistribute this source code, for commercial or non-commercial
- purposes, with the following restrictions: (1) the origin of this
- source code must not be misrepresented; (2) modified versions must
- be plainly marked as such; and (3) this notice may not be removed
- or altered from any source or modified source distribution.
*====================================================================*/
/*
* watershed.c
*
* Top-level
* L_WSHED *wshedCreate()
* void wshedDestroy()
* l_int32 wshedApply()
*
* Helpers
* static l_int32 identifyWatershedBasin()
* static l_int32 mergeLookup()
* static l_int32 wshedGetHeight()
* static void pushNewPixel()
* static void popNewPixel()
* static void pushWSPixel()
* static void popWSPixel()
* static void debugPrintLUT()
* static void debugWshedMerge()
*
* Output
* l_int32 wshedBasins()
* PIX *wshedRenderFill()
* PIX *wshedRenderColors()
*
* The watershed function identifies the "catch basins" of the input
* 8 bpp image, with respect to the specified seeds or "markers".
* The use is in segmentation, but the selection of the markers is
* critical to getting meaningful results.
*
* How are the markers selected? You can't simply use the local
* minima, because a typical image has sufficient noise so that
* a useful catch basin can easily have multiple local minima. However
* they are selected, the question for the watershed function is
* how to handle local minima that are not markers. The reason
* this is important is because of the algorithm used to find the
* watersheds, which is roughly like this:
*
* (1) Identify the markers and the local minima, and enter them
* into a priority queue based on the pixel value. Each marker
* is shrunk to a single pixel, if necessary, before the
* operation starts.
* (2) Feed the priority queue with neighbors of pixels that are
* popped off the queue. Each of these queue pixels is labelled
* with the index value of its parent.
* (3) Each pixel is also labelled, in a 32-bit image, with the marker
* or local minimum index, from which it was originally derived.
* (4) There are actually 3 classes of labels: seeds, minima, and
* fillers. The fillers are labels of regions that have already
* been identified as watersheds and are continuing to fill, for
* the purpose of finding higher watersheds.
* (5) When a pixel is popped that has already been labelled in the
* 32-bit image and that label differs from the label of its
* parent (stored in the queue pixel), a boundary has been crossed.
* There are several cases:
* (a) Both parents are derived from markers but at least one
* is not deep enough to become a watershed. Absorb the
* shallower basin into the deeper one, fixing the LUT to
* redirect the shallower index to the deeper one.
* (b) Both parents are derived from markers and both are deep
* enough. Identify and save the watershed for each marker.
* (c) One parent was derived from a marker and the other from
* a minima: absorb the minima basin into the marker basin.
* (d) One parent was derived from a marker and the other is
* a filler: identify and save the watershed for the marker.
* (e) Both parents are derived from minima: merge them.
* (f) One parent is a filler and the other is derived from a
* minima: merge the minima into the filler.
* (6) The output of the watershed operation consists of:
* - a pixa of the basins
* - a pta of the markers
* - a numa of the watershed levels
*
* Typical usage:
* L_WShed *wshed = wshedCreate(pixs, pixseed, mindepth, 0);
* wshedApply(wshed);
*
* wshedBasins(wshed, &pixa, &nalevels);
* ... do something with pixa, nalevels ...
* pixaDestroy(&pixa);
* numaDestroy(&nalevels);
*
* Pix *pixd = wshedRenderFill(wshed);
*
* wshedDestroy(&wshed);
*/
#include <stdio.h>
#include <stdlib.h>
#include "allheaders.h"
#ifndef NO_CONSOLE_IO
#define DEBUG_WATERSHED 0
#endif /* ~NO_CONSOLE_IO */
static const l_uint32 MAX_LABEL_VALUE = 0x7fffffff; /* largest l_int32 */
struct L_NewPixel
{
l_int32 x;
l_int32 y;
};
typedef struct L_NewPixel L_NEWPIXEL;
struct L_WSPixel
{
l_float32 val; /* pixel value */
l_int32 x;
l_int32 y;
l_int32 index; /* label for set to which pixel belongs */
};
typedef struct L_WSPixel L_WSPIXEL;
/* Static functions for obtaining bitmap of watersheds */
static void wshedSaveBasin(L_WSHED *wshed, l_int32 index, l_int32 level);
static l_int32 identifyWatershedBasin(L_WSHED *wshed,
l_int32 index, l_int32 level,
BOX **pbox, PIX **ppixd);
/* Static function for merging lut and backlink arrays */
static l_int32 mergeLookup(L_WSHED *wshed, l_int32 sindex, l_int32 dindex);
/* Static function for finding the height of the current pixel
above its seed or minima in the watershed. */
static l_int32 wshedGetHeight(L_WSHED *wshed, l_int32 val, l_int32 label,
l_int32 *pheight);
/* Static accessors for NewPixel on a queue */
static void pushNewPixel(L_QUEUE *lq, l_int32 x, l_int32 y,
l_int32 *pminx, l_int32 *pmaxx,
l_int32 *pminy, l_int32 *pmaxy);
static void popNewPixel(L_QUEUE *lq, l_int32 *px, l_int32 *py);
/* Static accessors for WSPixel on a heap */
static void pushWSPixel(L_HEAP *lh, L_STACK *stack, l_int32 val,
l_int32 x, l_int32 y, l_int32 index);
static void popWSPixel(L_HEAP *lh, L_STACK *stack, l_int32 *pval,
l_int32 *px, l_int32 *py, l_int32 *pindex);
/* Static debug print output */
static void debugPrintLUT(l_int32 *lut, l_int32 size, l_int32 debug);
static void debugWshedMerge(L_WSHED *wshed, char *descr, l_int32 x,
l_int32 y, l_int32 label, l_int32 index);
/*-----------------------------------------------------------------------*
* Top-level watershed *
*-----------------------------------------------------------------------*/
/*!
* wshedCreate()
*
* Input: pixs (8 bpp source)
* pixm (1 bpp 'marker' seed)
* mindepth (minimum depth; anything less is not saved)
* debugflag (1 for debug output)
* Return: WShed, or null on error
*
* Notes:
* (1) It is not necessary for the fg pixels in the seed image
* be at minima, or that they be isolated. We extract a
* single pixel from each connected component, and a seed
* anywhere in a watershed will eventually label the watershed
* when the filling level reaches it.
* (2) Set mindepth to some value to ignore noise in pixs that
* can create small local minima. Any watershed shallower
* than mindepth, even if it has a seed, will not be saved;
* It will either be incorporated in another watershed or
* eliminated.
*/
L_WSHED *
wshedCreate(PIX *pixs,
PIX *pixm,
l_int32 mindepth,
l_int32 debugflag)
{
l_int32 w, h;
L_WSHED *wshed;
PROCNAME("wshedCreate");
if (!pixs)
return (L_WSHED *)ERROR_PTR("pixs is not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (L_WSHED *)ERROR_PTR("pixs is not 8 bpp", procName, NULL);
if (!pixm)
return (L_WSHED *)ERROR_PTR("pixm is not defined", procName, NULL);
if (pixGetDepth(pixm) != 1)
return (L_WSHED *)ERROR_PTR("pixm is not 1 bpp", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
if (pixGetWidth(pixm) != w || pixGetHeight(pixm) != h)
return (L_WSHED *)ERROR_PTR("pixs/m sizes are unequal", procName, NULL);
if ((wshed = (L_WSHED *)CALLOC(1, sizeof(L_WSHED))) == NULL)
return (L_WSHED *)ERROR_PTR("wshed not made", procName, NULL);
wshed->pixs = pixClone(pixs);
wshed->pixm = pixClone(pixm);
wshed->mindepth = L_MAX(1, mindepth);
wshed->pixlab = pixCreate(w, h, 32);
pixSetAllArbitrary(wshed->pixlab, MAX_LABEL_VALUE);
wshed->pixt = pixCreate(w, h, 1);
wshed->lines8 = pixGetLinePtrs(pixs, NULL);
wshed->linem1 = pixGetLinePtrs(pixm, NULL);
wshed->linelab32 = pixGetLinePtrs(wshed->pixlab, NULL);
wshed->linet1 = pixGetLinePtrs(wshed->pixt, NULL);
wshed->debug = debugflag;
return wshed;
}
/*!
* wshedDestroy()
*
* Input: &wshed (<will be set to null before returning>)
* Return: void
*/
void
wshedDestroy(L_WSHED **pwshed)
{
l_int32 i;
L_WSHED *wshed;
PROCNAME("wshedDestroy");
if (pwshed == NULL) {
L_WARNING("ptr address is null!", procName);
return;
}
if ((wshed = *pwshed) == NULL)
return;
pixDestroy(&wshed->pixs);
pixDestroy(&wshed->pixm);
pixDestroy(&wshed->pixlab);
pixDestroy(&wshed->pixt);
if (wshed->lines8) FREE(wshed->lines8);
if (wshed->linem1) FREE(wshed->linem1);
if (wshed->linelab32) FREE(wshed->linelab32);
if (wshed->linet1) FREE(wshed->linet1);
pixaDestroy(&wshed->pixad);
ptaDestroy(&wshed->ptas);
numaDestroy(&wshed->nash);
numaDestroy(&wshed->nasi);
numaDestroy(&wshed->namh);
numaDestroy(&wshed->nalevels);
if (wshed->lut)
FREE(wshed->lut);
if (wshed->links) {
for (i = 0; i < wshed->arraysize; i++)
numaDestroy(&wshed->links[i]);
FREE(wshed->links);
}
FREE(wshed);
*pwshed = NULL;
return;
}
/*!
* wshedApply()
*
* Input: wshed (generated from wshedCreate())
* Return: 0 if OK, 1 on error
*
* Iportant note:
* (1) This is buggy. It seems to locate watersheds that are
* duplicates. The watershed extraction after complete fill
* grabs some regions belonging to existing watersheds.
* See prog/watershedtest.c for testing.
*/
l_int32
wshedApply(L_WSHED *wshed)
{
char two_new_watersheds[] = "Two new watersheds";
char seed_absorbed_into_seeded_basin[] = "Seed absorbed into seeded basin";
char one_new_watershed_label[] = "One new watershed (label)";
char one_new_watershed_index[] = "One new watershed (index)";
char minima_absorbed_into_seeded_basin[] =
"Minima absorbed into seeded basin";
char minima_absorbed_by_filler_or_another[] =
"Minima absorbed by filler or another";
l_int32 nseeds, nother, nboth, arraysize;
l_int32 i, j, val, x, y, w, h, index, mindepth;
l_int32 imin, imax, jmin, jmax, cindex, clabel, nindex;
l_int32 hindex, hlabel, hmin, hmax, minhindex, maxhindex;
l_int32 *lut;
l_uint32 ulabel, uval;
void **lines8, **linelab32;
NUMA *nalut, *nalevels, *nash, *namh, *nasi;
NUMA **links;
L_HEAP *lh;
PIX *pixmin, *pixsd;
PIXA *pixad;
L_STACK *rstack;
PTA *ptas, *ptao;
PROCNAME("wshedApply");
if (!wshed)
return ERROR_INT("wshed not defined", procName, 1);
/* ------------------------------------------------------------ *
* Initialize priority queue and pixlab with seeds and minima *
* ------------------------------------------------------------ */
lh = lheapCreate(0, L_SORT_INCREASING); /* remove lowest values first */
rstack = lstackCreate(0); /* for reusing the WSPixels */
pixGetDimensions(wshed->pixs, &w, &h, NULL);
lines8 = wshed->lines8; /* wshed owns this */
linelab32 = wshed->linelab32; /* ditto */
/* Identify seed (marker) pixels, 1 for each c.c. in pixm */
ptas = pixSelectMinInConnComp(wshed->pixs, wshed->pixm, &nash);
pixsd = pixGenerateFromPta(ptas, w, h);
nseeds = ptaGetCount(ptas);
for (i = 0; i < nseeds; i++) {
ptaGetIPt(ptas, i, &x, &y);
uval = GET_DATA_BYTE(lines8[y], x);
pushWSPixel(lh, rstack, (l_int32)uval, x, y, i);
}
wshed->ptas = ptas;
nasi = numaMakeConstant(1, nseeds); /* indicator array */
wshed->nasi = nasi;
wshed->nash = nash;
wshed->nseeds = nseeds;
/* Identify minima that are not seeds. Use these 4 steps:
* (1) Get the local minima, which can have components
* of arbitrary size. This will be a clipping mask.
* (2) Get the image of the actual seeds (pixsd)
* (3) Remove all elements of the clipping mask that have a seed.
* (4) Shrink each of the remaining elements of the minima mask
* to a single pixel. */
pixLocalExtrema(wshed->pixs, 200, 0, &pixmin, NULL);
pixRemoveSeededComponents(pixmin, pixsd, pixmin, 8, 2);
ptao = pixSelectMinInConnComp(wshed->pixs, pixmin, &namh);
nother = ptaGetCount(ptao);
for (i = 0; i < nother; i++) {
ptaGetIPt(ptao, i, &x, &y);
uval = GET_DATA_BYTE(lines8[y], x);
pushWSPixel(lh, rstack, (l_int32)uval, x, y, nseeds + i);
}
wshed->namh = namh;
/* ------------------------------------------------------------ *
* Initialize merging lookup tables *
* ------------------------------------------------------------ */
/* nalut should always give the current after-merging index.
* links are effectively backpointers: they are numas associated with
* a dest index of all indices in nalut that point to that index. */
mindepth = wshed->mindepth;
nboth = nseeds + nother;
arraysize = 2 * nboth;
wshed->arraysize = arraysize;
nalut = numaMakeSequence(0, 1, arraysize);
lut = numaGetIArray(nalut);
wshed->lut = lut; /* wshed owns this */
links = (NUMA **)CALLOC(arraysize, sizeof(NUMA *));
wshed->links = links; /* wshed owns this */
nindex = nseeds + nother; /* the next unused index value */
/* ------------------------------------------------------------ *
* Fill the basins, using the priority queue *
* ------------------------------------------------------------ */
pixad = pixaCreate(nseeds);
wshed->pixad = pixad; /* wshed owns this */
nalevels = numaCreate(nseeds);
wshed->nalevels = nalevels; /* wshed owns this */
L_INFO_INT2("nseeds = %d, nother = %d\n", procName, nseeds, nother);
while (lheapGetCount(lh) > 0) {
popWSPixel(lh, rstack, &val, &x, &y, &index);
/* fprintf(stderr, "x = %d, y = %d, index = %d\n", x, y, index); */
ulabel = GET_DATA_FOUR_BYTES(linelab32[y], x);
if (ulabel == MAX_LABEL_VALUE)
clabel = ulabel;
else
clabel = lut[ulabel];
cindex = lut[index];
if (clabel == cindex) continue; /* have already seen this one */
if (clabel == MAX_LABEL_VALUE) { /* new one; assign index and try to
* propagate to all neighbors */
SET_DATA_FOUR_BYTES(linelab32[y], x, cindex);
imin = L_MAX(0, y - 1);
imax = L_MIN(h - 1, y + 1);
jmin = L_MAX(0, x - 1);
jmax = L_MIN(w - 1, x + 1);
for (i = imin; i <= imax; i++) {
for (j = jmin; j <= jmax; j++) {
if (i == y && j == x) continue;
uval = GET_DATA_BYTE(lines8[i], j);
pushWSPixel(lh, rstack, (l_int32)uval, j, i, cindex);
}
}
}
else { /* this pixel is already labeled (differently); must resolve */
/* If both indices are seeds, check if the min height is
* greater than mindepth. If so, we have two new watersheds;
* locate them and assign to both regions a new index
* for further waterfill. If not, absorb the shallower
* watershed into the deeper one and continue filling it. */
pixGetPixel(pixsd, x, y, &uval);
if (clabel < nseeds && cindex < nseeds) {
wshedGetHeight(wshed, val, clabel, &hlabel);
wshedGetHeight(wshed, val, cindex, &hindex);
hmin = L_MIN(hlabel, hindex);
hmax = L_MAX(hlabel, hindex);
if (hmin == hmax) {
hmin = hlabel;
hmax = hindex;
}
if (wshed->debug) {
fprintf(stderr, "clabel,hlabel = %d,%d\n", clabel, hlabel);
fprintf(stderr, "hmin = %d, hmax = %d\n", hmin, hmax);
fprintf(stderr, "cindex,hindex = %d,%d\n", cindex, hindex);
if (hmin < mindepth)
fprintf(stderr, "Too shallow!\n");
}
if (hmin >= mindepth) {
debugWshedMerge(wshed, two_new_watersheds,
x, y, clabel, cindex);
wshedSaveBasin(wshed, cindex, val - 1);
wshedSaveBasin(wshed, clabel, val - 1);
numaSetValue(nasi, cindex, 0);
numaSetValue(nasi, clabel, 0);
if (wshed->debug) fprintf(stderr, "nindex = %d\n", nindex);
debugPrintLUT(lut, nindex, wshed->debug);
mergeLookup(wshed, clabel, nindex);
debugPrintLUT(lut, nindex, wshed->debug);
mergeLookup(wshed, cindex, nindex);
debugPrintLUT(lut, nindex, wshed->debug);
nindex++;
}
else /* extraneous seed within seeded basin; absorb */
debugWshedMerge(wshed, seed_absorbed_into_seeded_basin,
x, y, clabel, cindex);
maxhindex = clabel;
minhindex = cindex;
if (hindex > hlabel) {
maxhindex = cindex;
minhindex = clabel;
}
mergeLookup(wshed, minhindex, maxhindex);
}
/* If one index is a seed and the other is a merge of
* 2 watersheds, generate a single watershed. */
else if (clabel < nseeds && cindex >= nboth) {
debugWshedMerge(wshed, one_new_watershed_label,
x, y, clabel, cindex);
wshedSaveBasin(wshed, clabel, val - 1);
numaSetValue(nasi, clabel, 0);
mergeLookup(wshed, clabel, cindex);
}
else if (cindex < nseeds && clabel >= nboth) {
debugWshedMerge(wshed, one_new_watershed_index,
x, y, clabel, cindex);
wshedSaveBasin(wshed, cindex, val - 1);
numaSetValue(nasi, cindex, 0);
mergeLookup(wshed, cindex, clabel);
}
/* If one index is a seed and the other is from a minimum,
* merge the minimum wshed into the seed wshed. */
else if (clabel < nseeds) { /* cindex from minima; absorb */
debugWshedMerge(wshed, minima_absorbed_into_seeded_basin,
x, y, clabel, cindex);
mergeLookup(wshed, cindex, clabel);
}
else if (cindex < nseeds) { /* clabel from minima; absorb */
debugWshedMerge(wshed, minima_absorbed_into_seeded_basin,
x, y, clabel, cindex);
mergeLookup(wshed, clabel, cindex);
}
/* If neither index is a seed, just merge */
else {
debugWshedMerge(wshed, minima_absorbed_by_filler_or_another,
x, y, clabel, cindex);
mergeLookup(wshed, clabel, cindex);
}
}
}
#if 0
/* Use the indicator array to save any watersheds that fill
* to the maximum value. This seems to screw things up! */
for (i = 0; i < nseeds; i++) {
numaGetIValue(nasi, i, &ival);
if (ival == 1) {
wshedSaveBasin(wshed, lut[i], val - 1);
numaSetValue(nasi, i, 0);
}
}
#endif
numaDestroy(&nalut);
pixDestroy(&pixmin);
pixDestroy(&pixsd);
ptaDestroy(&ptao);
lheapDestroy(&lh, TRUE);
lstackDestroy(&rstack, TRUE);
return 0;
}
/*-----------------------------------------------------------------------*
* Helpers *
*-----------------------------------------------------------------------*/
/*!
* wshedSaveBasin()
*
* Input: wshed
* index (index of basin to be located)
* level (filling level reached at the time this function
* is called)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This identifies a single watershed. It does not change
* the LUT, which must be done subsequently.
* (2) The fill level of a basin is taken to be @level - 1.
*/
static void
wshedSaveBasin(L_WSHED *wshed,
l_int32 index,
l_int32 level)
{
BOX *box;
PIX *pix;
PROCNAME("wshedSaveBasin");
if (!wshed)
return ERROR_VOID("wshed not defined", procName);
if (identifyWatershedBasin(wshed, index, level, &box, &pix) == 0) {
pixaAddPix(wshed->pixad, pix, L_INSERT);
pixaAddBox(wshed->pixad, box, L_INSERT);
numaAddNumber(wshed->nalevels, level - 1);
}
return;
}
/*!
* identifyWatershedBasin()
*
* Input: wshed
* index (index of basin to be located)
* level (of basin at point at which the two basins met)
* &box (<return> bounding box of basin)
* &pixd (<return> pix of basin, cropped to its bounding box)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) This is a static function, so we assume pixlab, pixs and pixt
* exist and are the same size.
* (2) It selects all pixels that have the label @index in pixlab
* and that have a value in pixs that is less than @level.
* (3) It is used whenever two seeded basins meet (typically at a saddle),
* or when one seeded basin meets a 'filler'. All identified
* basins are saved as a watershed.
*/
static l_int32
identifyWatershedBasin(L_WSHED *wshed,
l_int32 index,
l_int32 level,
BOX **pbox,
PIX **ppixd)
{
l_int32 imin, imax, jmin, jmax, minx, miny, maxx, maxy;
l_int32 bw, bh, i, j, w, h, x, y;
l_int32 *lut;
l_uint32 label, bval, lval;
void **lines8, **linelab32, **linet1;
BOX *box;
PIX *pixs, *pixlab, *pixt, *pixd;
L_QUEUE *lq;
PROCNAME("identifyWatershedBasin");
if (!pbox)
return ERROR_INT("&box not defined", procName, 1);
*pbox = NULL;
if (!ppixd)
return ERROR_INT("&pixd not defined", procName, 1);
*ppixd = NULL;
if (!wshed)
return ERROR_INT("wshed not defined", procName, 1);
/* Make a queue and an auxiliary stack */
lq = lqueueCreate(0);
lq->stack = lstackCreate(0);
pixs = wshed->pixs;
pixlab = wshed->pixlab;
pixt = wshed->pixt;
lines8 = wshed->lines8;
linelab32 = wshed->linelab32;
linet1 = wshed->linet1;
lut = wshed->lut;
pixGetDimensions(pixs, &w, &h, NULL);
/* Prime the queue with the seed pixel for this watershed. */
minx = miny = 1000000;
maxx = maxy = 0;
ptaGetIPt(wshed->ptas, index, &x, &y);
pixSetPixel(pixt, x, y, 1);
pushNewPixel(lq, x, y, &minx, &maxx, &miny, &maxy);
if (wshed->debug) fprintf(stderr, "prime: (x,y) = (%d, %d)\n", x, y);
/* Each pixel in a spreading breadth-first search is inspected.
* It is accepted as part of this watershed, and pushed on
* the search queue, if:
* (1) It has a label value equal to @index
* (2) The pixel value is less than @level, the overflow
* height at which the two basins join.
* (3) It has not yet been seen in this search. */
while (lqueueGetCount(lq) > 0) {
popNewPixel(lq, &x, &y);
imin = L_MAX(0, y - 1);
imax = L_MIN(h - 1, y + 1);
jmin = L_MAX(0, x - 1);
jmax = L_MIN(w - 1, x + 1);
for (i = imin; i <= imax; i++) {
for (j = jmin; j <= jmax; j++) {
if (j == x && i == y) continue; /* parent */
label = GET_DATA_FOUR_BYTES(linelab32[i], j);
if (label == MAX_LABEL_VALUE || lut[label] != index) continue;
bval = GET_DATA_BIT(linet1[i], j);
if (bval == 1) continue; /* already seen */
lval = GET_DATA_BYTE(lines8[i], j);
if (lval >= level) continue; /* too high */
SET_DATA_BIT(linet1[i], j);
pushNewPixel(lq, j, i, &minx, &maxx, &miny, &maxy);
}
}
}
/* Extract the box and pix, and clear pixt */
bw = maxx - minx + 1;
bh = maxy - miny + 1;
box = boxCreate(minx, miny, bw, bh);
pixd = pixClipRectangle(pixt, box, NULL);
pixRasterop(pixt, minx, miny, bw, bh, PIX_SRC ^ PIX_DST, pixd, 0, 0);
*pbox = box;
*ppixd = pixd;
lqueueDestroy(&lq, 1);
return 0;
}
/*!
* mergeLookup()
*
* Input: wshed
* sindex (primary index being changed in the merge)
* dindex (index that @sindex will point to after the merge)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) The links are a sparse array of Numas showing current back-links.
* The lut gives the current index (of the seed or the minima
* for the wshed in which it is located.
* (2) Think of each entry in the lut. There are two types:
* owner: lut[index] = index
* redirect: lut[index] != index
* (3) This is called each time a merge occurs. It puts the lut
* and backlinks in a canonical form after the merge, where
* all entries in the lut point to the current "owner", which
* has all backlinks. That is, every "redirect" in the lut
* points to an "owner". The lut always gives the index of
* the current owner.
*/
static l_int32
mergeLookup(L_WSHED *wshed,
l_int32 sindex,
l_int32 dindex)
{
l_int32 i, n, size, index;
l_int32 *lut;
NUMA *na;
NUMA **links;
PROCNAME("mergeLookup");
if (!wshed)
return ERROR_INT("wshed not defined", procName, 1);
size = wshed->arraysize;
if (sindex < 0 || sindex >= size)
return ERROR_INT("invalid sindex", procName, 1);
if (dindex < 0 || dindex >= size)
return ERROR_INT("invalid dindex", procName, 1);
/* Redirect links in the lut */
n = 0;
links = wshed->links;
lut = wshed->lut;
if ((na = links[sindex]) != NULL) {
n = numaGetCount(na);
for (i = 0; i < n; i++) {
numaGetIValue(na, i, &index);
lut[index] = dindex;
}
}
lut[sindex] = dindex;
/* Shift the backlink arrays from sindex to dindex.
* sindex should have no backlinks because all entries in the
* lut that were previously pointing to it have been redirected
* to dindex. */
if (!links[dindex])
links[dindex] = numaCreate(n);
numaJoin(links[dindex], links[sindex], 0, 0);
numaAddNumber(links[dindex], sindex);
numaDestroy(&links[sindex]);
return 0;
}
/*!
* wshedGetHeight()
*
* Input: wshed (array of current indices)
* val (value of current pixel popped off queue)
* label (of pixel or 32 bpp label image)
* &height (<return> height of current value from seed
* or minimum of watershed)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) It is only necessary to find the height for a watershed
* that is indexed by a seed or a minima. This function should
* not be called on a finished watershed (that continues to fill).
*/
static l_int32
wshedGetHeight(L_WSHED *wshed,
l_int32 val,
l_int32 label,
l_int32 *pheight)
{
l_int32 minval;
PROCNAME("wshedGetHeight");
if (!pheight)
return ERROR_INT("&height not defined", procName, 1);
*pheight = 0;
if (!wshed)
return ERROR_INT("wshed not defined", procName, 1);
if (label < wshed->nseeds)
numaGetIValue(wshed->nash, label, &minval);
else if (label < wshed->nseeds + wshed->nother)
numaGetIValue(wshed->namh, label, &minval);
else
return ERROR_INT("finished watershed; should not call", procName, 1);
*pheight = val - minval;
return 0;
}
/*
* pushNewPixel()
*
* Input: lqueue
* x, y (pixel coordinates)
* &minx, &maxx, &miny, &maxy (<return> bounding box update)
* Return: void
*
* Notes:
* (1) This is a wrapper for adding a NewPixel to a queue, which
* updates the bounding box for all pixels on that queue and
* uses the storage stack to retrieve a NewPixel.
*/
static void
pushNewPixel(L_QUEUE *lq,
l_int32 x,
l_int32 y,
l_int32 *pminx,
l_int32 *pmaxx,
l_int32 *pminy,
l_int32 *pmaxy)
{
L_NEWPIXEL *np;
PROCNAME("pushNewPixel");
if (!lq)
return ERROR_VOID(procName, "queue not defined");
/* Adjust bounding box */
*pminx = L_MIN(*pminx, x);
*pmaxx = L_MAX(*pmaxx, x);
*pminy = L_MIN(*pminy, y);
*pmaxy = L_MAX(*pmaxy, y);
/* Get a newpixel to use */
if (lstackGetCount(lq->stack) > 0)
np = (L_NEWPIXEL *)lstackRemove(lq->stack);
else
np = (L_NEWPIXEL *)CALLOC(1, sizeof(L_NEWPIXEL));
np->x = x;
np->y = y;
lqueueAdd(lq, np);
return;
}
/*
* popNewPixel()
*
* Input: lqueue
* &x, &y (<return> pixel coordinates)
* Return: void
*
* Notes:
* (1) This is a wrapper for removing a NewPixel from a queue,
* which returns the pixel coordinates and saves the NewPixel
* on the storage stack.
*/
static void
popNewPixel(L_QUEUE *lq,
l_int32 *px,
l_int32 *py)
{
L_NEWPIXEL *np;
PROCNAME("popNewPixel");
if (!lq)
return ERROR_VOID(procName, "lqueue not defined");
if ((np = (L_NEWPIXEL *)lqueueRemove(lq)) == NULL)
return;
*px = np->x;
*py = np->y;
lstackAdd(lq->stack, np); /* save for re-use */
return;
}
/*
* pushWSPixel()
*
* Input: lh (priority queue)
* stack (of reusable WSPixels)
* val (pixel value: used for ordering the heap)
* x, y (pixel coordinates)
* index (label for set to which pixel belongs)
* Return: void
*
* Notes:
* (1) This is a wrapper for adding a WSPixel to a heap. It
* uses the storage stack to retrieve a WSPixel.
*/
static void
pushWSPixel(L_HEAP *lh,
L_STACK *stack,
l_int32 val,
l_int32 x,
l_int32 y,
l_int32 index)
{
L_WSPIXEL *wsp;
PROCNAME("pushWSPixel");
if (!lh)
return ERROR_VOID(procName, "heap not defined");
if (!stack)
return ERROR_VOID(procName, "stack not defined");
/* Get a wspixel to use */
if (lstackGetCount(stack) > 0)
wsp = (L_WSPIXEL *)lstackRemove(stack);
else
wsp = (L_WSPIXEL *)CALLOC(1, sizeof(L_WSPIXEL));
wsp->val = (l_float32)val;
wsp->x = x;
wsp->y = y;
wsp->index = index;
lheapAdd(lh, wsp);
return;
}
/*
* popWSPixel()
*
* Input: lh (priority queue)
* stack (of reusable WSPixels)
* &val (<return> pixel value)
* &x, &y (<return> pixel coordinates)
* &index (<return> label for set to which pixel belongs)
* Return: void
*
* Notes:
* (1) This is a wrapper for removing a WSPixel from a heap,
* which returns the WSPixel data and saves the WSPixel
* on the storage stack.
*/
static void
popWSPixel(L_HEAP *lh,
L_STACK *stack,
l_int32 *pval,
l_int32 *px,
l_int32 *py,
l_int32 *pindex)
{
L_WSPIXEL *wsp;
PROCNAME("popWSPixel");
if (!lh)
return ERROR_VOID(procName, "lheap not defined");
if (!stack)
return ERROR_VOID(procName, "stack not defined");
if (!pval || !px || !py || !pindex)
return ERROR_VOID(procName, "data can't be returned");
if ((wsp = (L_WSPIXEL *)lheapRemove(lh)) == NULL)
return;
*pval = (l_int32)wsp->val;
*px = wsp->x;
*py = wsp->y;
*pindex = wsp->index;
lstackAdd(stack, wsp); /* save for re-use */
return;
}
static void
debugPrintLUT(l_int32 *lut,
l_int32 size,
l_int32 debug)
{
l_int32 i;
if (!debug) return;
fprintf(stderr, "lut: ");
for (i = 0; i < size; i++)
fprintf(stderr, "%d ", lut[i]);
fprintf(stderr, "\n");
return;
}
static void
debugWshedMerge(L_WSHED *wshed,
char *descr,
l_int32 x,
l_int32 y,
l_int32 label,
l_int32 index)
{
if (!wshed || (wshed->debug == 0))
return;
fprintf(stderr, "%s:\n", descr);
fprintf(stderr, " (x, y) = (%d, %d)\n", x, y);
fprintf(stderr, " clabel = %d, cindex = %d\n", label, index);
return;
}
/*-----------------------------------------------------------------------*
* Output *
*-----------------------------------------------------------------------*/
/*!
* wshedBasins()
*
* Input: wshed
* &pixa (<optional return> mask of watershed basins)
* &nalevels (<optional return> watershed levels)
* Return: 0 if OK, 1 on error
*/
l_int32
wshedBasins(L_WSHED *wshed,
PIXA **ppixa,
NUMA **pnalevels)
{
PROCNAME("wshedBasins");
if (!wshed)
return ERROR_INT("wshed not defined", procName, 1);
if (ppixa)
*ppixa = pixaCopy(wshed->pixad, L_CLONE);
if (pnalevels)
*pnalevels = numaClone(wshed->nalevels);
return 0;
}
/*!
* wshedRenderFill()
*
* Input: wshed
* Return: pixd (initial image with all basins filled), or null on error
*/
PIX *
wshedRenderFill(L_WSHED *wshed)
{
l_int32 i, n, level, bx, by;
NUMA *na;
PIX *pix, *pixd;
PIXA *pixa;
PROCNAME("wshedRenderFill");
if (!wshed)
return (PIX *)ERROR_PTR("wshed not defined", procName, NULL);
wshedBasins(wshed, &pixa, &na);
pixd = pixCopy(NULL, wshed->pixs);
n = pixaGetCount(pixa);
for (i = 0; i < n; i++) {
pix = pixaGetPix(pixa, i, L_CLONE);
pixaGetBoxGeometry(pixa, i, &bx, &by, NULL, NULL);
numaGetIValue(na, i, &level);
pixPaintThroughMask(pixd, pix, bx, by, level);
pixDestroy(&pix);
}
pixaDestroy(&pixa);
numaDestroy(&na);
return pixd;
}
/*!
* wshedRenderColors()
*
* Input: wshed
* Return: pixd (initial image with all basins filled), or null on error
*/
PIX *
wshedRenderColors(L_WSHED *wshed)
{
l_int32 w, h;
PIX *pixg, *pixt, *pixc, *pixm, *pixd;
PIXA *pixa;
PROCNAME("wshedRenderColors");
if (!wshed)
return (PIX *)ERROR_PTR("wshed not defined", procName, NULL);
wshedBasins(wshed, &pixa, NULL);
pixg = pixCopy(NULL, wshed->pixs);
pixGetDimensions(wshed->pixs, &w, &h, NULL);
pixd = pixConvertTo32(pixg);
pixt = pixaDisplayRandomCmap(pixa, w, h);
pixc = pixConvertTo32(pixt);
pixm = pixaDisplay(pixa, w, h);
pixCombineMasked(pixd, pixc, pixm);
pixDestroy(&pixg);
pixDestroy(&pixt);
pixDestroy(&pixc);
pixDestroy(&pixm);
pixaDestroy(&pixa);
return pixd;
}