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/* file: erfill.mex.c
** description: Extremal Regions filling
** author: Andrea Vedaldi
**/
/* AUTORIGHTS
Copyright (C) 2006 Regents of the University of California
All rights reserved
Written by Andrea Vedaldi (UCLA VisionLab).
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the University of California, Berkeley nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @file
** @brief Maximally Stable Extremal Regions - MEX implementation
**/
#include<mexutils.c>
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
#include<assert.h>
#define MIN(x,y) (((x)<(y))?(x):(y))
#define MAX(x,y) (((x)>(y))?(x):(y))
typedef char unsigned val_t ;
typedef int unsigned idx_t ;
typedef long long int unsigned acc_t ;
/* advance N-dimensional subscript */
void
adv(int const* dims, int ndims, int* subs_pt)
{
int d = 0 ;
while(d < ndims) {
if( ++subs_pt[d] < dims[d] ) return ;
subs_pt[d++] = 0 ;
}
}
/* driver */
void
mexFunction(int nout, mxArray *out[],
int nin, const mxArray *in[])
{
enum {IN_I=0, IN_ER} ;
enum {OUT_MEMBERS} ;
idx_t i ;
int k, nel, ndims ;
int const * dims ;
val_t const * I_pt ;
int last = 0 ;
int last_expanded = 0 ;
val_t value = 0 ;
double const * er_pt ;
int* subs_pt ; /* N-dimensional subscript */
int* nsubs_pt ; /* diff-subscript to point to neigh. */
idx_t* strides_pt ; /* strides to move in image array */
val_t* visited_pt ; /* flag */
idx_t* members_pt ; /* region members */
/** -----------------------------------------------------------------
** Check the arguments
** -------------------------------------------------------------- */
if (nin != 2) {
mexErrMsgTxt("Two arguments required.") ;
} else if (nout > 4) {
mexErrMsgTxt("Too many output arguments.");
}
if(mxGetClassID(in[IN_I]) != mxUINT8_CLASS) {
mexErrMsgTxt("I must be of class UINT8.") ;
}
if(!uIsRealScalar(in[IN_ER])) {
mexErrMsgTxt("ER must be a DOUBLE scalar.") ;
}
/* get dimensions */
nel = mxGetNumberOfElements(in[IN_I]) ;
ndims = mxGetNumberOfDimensions(in[IN_I]) ;
dims = mxGetDimensions(in[IN_I]) ;
I_pt = mxGetData(in[IN_I]) ;
/* allocate stuff */
subs_pt = mxMalloc( sizeof(int) * ndims ) ;
nsubs_pt = mxMalloc( sizeof(int) * ndims ) ;
strides_pt = mxMalloc( sizeof(idx_t) * ndims ) ;
visited_pt = mxMalloc( sizeof(val_t) * nel ) ;
members_pt = mxMalloc( sizeof(idx_t) * nel ) ;
er_pt = mxGetPr(in[IN_ER]) ;
/* compute strides to move into the N-dimensional image array */
strides_pt [0] = 1 ;
for(k = 1 ; k < ndims ; ++k) {
strides_pt [k] = strides_pt [k-1] * dims [k-1] ;
}
/* load first pixel */
memset(visited_pt, 0, sizeof(val_t) * nel) ;
{
idx_t idx = (idx_t) *er_pt ;
if( idx < 1 || idx > nel ) {
char buff[80] ;
snprintf(buff,80,"ER=%d out of range [1,%d]",idx,nel) ;
mexErrMsgTxt(buff) ;
}
members_pt [last++] = idx - 1 ;
}
value = I_pt[ members_pt[0] ] ;
/* -----------------------------------------------------------------
* Fill region
* -------------------------------------------------------------- */
while(last_expanded < last) {
/* pop next node xi */
idx_t index = members_pt[last_expanded++] ;
/* convert index into a subscript sub; also initialize nsubs
to (-1,-1,...,-1) */
{
idx_t temp = index ;
for(k = ndims-1 ; k >=0 ; --k) {
nsubs_pt [k] = -1 ;
subs_pt [k] = temp / strides_pt [k] ;
temp = temp % strides_pt [k] ;
}
}
/* process neighbors of xi */
while( true ) {
int good = true ;
idx_t nindex = 0 ;
/* compute NSUBS+SUB, the correspoinding neighbor index NINDEX
and check that the pixel is within image boundaries. */
for(k = 0 ; k < ndims && good ; ++k) {
int temp = nsubs_pt [k] + subs_pt [k] ;
good &= 0 <= temp && temp < dims[k] ;
nindex += temp * strides_pt [k] ;
}
/* process neighbor
1 - the pixel is within image boundaries;
2 - the pixel is indeed different from the current node
(this happens when nsub=(0,0,...,0));
3 - the pixel has value not greather than val
is a pixel older than xi
4 - the pixel has not been visited yet
*/
if(good
&& nindex != index
&& I_pt [nindex] <= value
&& ! visited_pt [nindex] ) {
/* mark as visited */
visited_pt [nindex] = 1 ;
/* add to list */
members_pt [last++] = nindex ;
}
/* move to next neighbor */
k = 0 ;
while(++ nsubs_pt [k] > 1) {
nsubs_pt [k++] = -1 ;
if(k == ndims) goto done_all_neighbors ;
}
} /* next neighbor */
done_all_neighbors : ;
} /* goto pop next member */
/*
* Save results
*/
{
int dims[2] ;
int unsigned * pt ;
dims[0] = last ;
out[OUT_MEMBERS] = mxCreateNumericArray(1,dims,mxUINT32_CLASS,mxREAL);
pt = mxGetData(out[OUT_MEMBERS]) ;
for (i = 0 ; i < last ; ++i) {
*pt++ = members_pt[i] + 1 ;
}
}
/* free stuff */
mxFree( members_pt ) ;
mxFree( visited_pt ) ;
mxFree( strides_pt ) ;
mxFree( nsubs_pt ) ;
mxFree( subs_pt ) ;
}
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