eddys_snippets/erosion-dilation/cclabling_1.h

/*
 * cclabling_1.h - inner part of functions cclabel4_1 and cclabel8_1
 *
 * Copyright 2013 Edward V. Emelianoff <eddy@sao.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

double t0 = dtime();

	CCbox *ret = NULL;
	size_t N = 0, // current label
		Nmax = W*H/4; // max number of labels
	size_t *labels = char2st(I, W, H, W_0);
	int w = W - 1, h = H - 1;
//printf("time for char2st: %gs\n", dtime()-t0);
	int y;
	size_t *assoc = Malloc(Nmax, sizeof(size_t)); // allocate memory for "remark" array
	size_t last_assoc_idx = 0; // last index filled in assoc array
	size_t currentnum = 0; // current pixel number
	inline void remark(size_t old, size_t new){ // remark in assoc[] pixel with value old to assoc[new] or vice versa
		size_t New = assoc[new], Old = assoc[old];
		if(Old == New){
			DBG("components equal (%zd->%zd and %zd->%zd)\n", old, Old, new, New);
			return;
		}
		DBG("N=%zd, curr=%zd, old:%zd->%zd <-> new:%zd->%zd ", N, currentnum, old, Old, new, New);
		// now we must check Old: if  Old<New we should swap them
		if(Old < New){
			register size_t _tmp_ = Old; Old = New; New = _tmp_; // swap values
			_tmp_ = old; old = new; new = _tmp_;
		}
		// decrement counters for current value (because we make merging)
		--currentnum;
		//OMP_FOR()
		for(size_t i = 1; i < last_assoc_idx; ++i){
			size_t m = assoc[i];
			DBG("assoc[%zd]=%zd ", i, m);
			if(m < Old) continue; // lower values
			if(m == Old){ // change all old markers to new
				assoc[i] = New;
				DBG("remark %zd->%zd to ->%zd ", i, m, New);
			}else{ // decrement all higher values
				DBG("decr %zd->%zd, ", i, m);
				assoc[i]--;
			}
		}
		DBG("\n");
	}
	//t0 = dtime();
	size_t *ptr = labels;
	for(y = 0; y < H; y++){
		bool found = false;
		size_t curmark = 0; // mark of pixel to the left
		for(int x = 0; x < W; x++, ptr++){
			size_t curval = *ptr;
			if(!curval){ found = false; continue;}
			size_t *U = (y) ? &ptr[-W] : NULL;
			size_t upmark = 0; // mark from line above
			if(!found){ // new pixel, check neighbours above
				found = true;
				// now check neighbours in upper string:
				if(U){
					#ifdef LABEL_8
					if(x && U[-1]){ // there is something in upper left corner -> use its value
						upmark = U[-1];
					}else // check point above only if there's nothing in left up
					#endif
						if(U[0]) upmark = U[0];
					#ifdef LABEL_8
					if(x < w && U[1]){ // there's something in upper right
						if(upmark){ // to the left of it was pixels
							remark(U[1], upmark);
						}else
							upmark = U[1];
					}
					#endif
				}
				if(!upmark){ // there's nothing above - set current pixel to incremented counter
					DBG("line #%d (w = %d) ", y, h);
					#ifdef LABEL_8  // check, whether pixel is not single
					size_t *D = (y < h) ? &ptr[W] : NULL;
					if(  !(x && ((D && D[-1]) /*|| ptr[-1]*/))   // no left neighbours
					  && !(x < w && ((D && D[1]) || ptr[1])) // no right neighbours
					  && !(D && D[0])){ // no neighbour down
						*ptr = 0; // erase this hermit!
						DBG("hermit!\n");
						continue;
					}
					#else
					// no neighbour down & neighbour to the right -> hermit
					if((y < h && ptr[W] == 0) && (x < w && ptr[1] == 0)){
						*ptr = 0; // erase this hermit!
						DBG("hermit!\n");
						continue;
					}
					#endif
					upmark = ++N;
					assoc[upmark] = ++currentnum; // refresh "assoc"
					DBG("assoc[%zd] = %zd\n", upmark, currentnum);
					last_assoc_idx = upmark + 1;
				}
				*ptr = upmark;
				curmark = upmark;
			}else{ // there was something to the left -> we must chek only U[1]
				if(U){
					if(x < w && U[1]){ // there's something in upper right
						remark(U[1], curmark);
					}
				}
				*ptr = curmark;
			}
		}
	}
//printf("time for step 2: %gs, found %zd objects\n", dtime()-t0, currentnum);
	DBG("Initial mark\n");
	#ifdef EBUG
for(y = 0; y < H; y++){
	size_t *ptr = &labels[y*W];
	for(int x = 0; x < W; x++, ptr++){
		if(*ptr) printf("%02zx", *ptr);
		else printf("  ");
	}
	printf("\n");
}
	#endif

//t0 = dtime();
	// Step 2: rename markers
	DBG("rename markers\n");
	// first correct complex assotiations in assoc
	OMP_FOR()
	for(y = 0; y < H; y++){
		size_t *ptr = &labels[y*W];
		for(int x = 0; x < W; x++, ptr++){
			size_t p = *ptr;
			if(!p){continue;}
			*ptr = assoc[p];
		}
	}
//printf("time for step 3: %gs\n", dtime()-t0);
#ifdef EBUG
printf("\n\n");
for(y = 0; y < H; y++){
	size_t *ptr = &labels[y*W];
	for(int x = 0; x < W; x++, ptr++){
		if(*ptr) printf("%02zx", *ptr);
		else printf("  ");
	}
	printf("\n");
}
#endif
	FREE(assoc);
	FREE(labels);
printf("%6.4f\t%zd\n", dtime()-t0, currentnum);