libvips/libsrc/arithmetic/im_stats.c
2008-11-02 22:11:01 +00:00

281 lines
6.9 KiB
C

/* @(#) im_stats: find general image statistics for all bands separately
(C) Kirk Martinez 1993
23/4/93 J.Cupitt
- adapted to partial images
- special struct abandoned; now returns DOUBLEMASK.
1/7/93 JC
- adapted for partial v2
- ANSIfied
27/7/93 JC
- init of mask changed to use actual values, not IM_MAXDOUBLE and
(-IM_MAXDOUBLE). These caused problems when assigned to floats.
funny business with offset==42, yuk!
31/8/93 JC
- forgot to init global max/min properly! sorry.
21/6/95 JC
- still did not init max and min correctly --- now fixed for good
* 13/1/05
* - use 64 bit arithmetic
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Make and initialise a DOUBLEMASK suitable for grabbing statistics.
*/
static void *
make_mask( IMAGE *im, void *a, void *b )
{
DOUBLEMASK *out;
/* Make temp output.
*/
if( !(out = im_create_dmask( "stats", 6, im->Bands + 1 )) )
return( NULL );
/* Set offset to magic value: 42 indicates we have not yet initialised
* max and min for this mask.
*/
out->offset = 42;
return( out );
}
/* Merge a temp DOUBLEMASK into the real DOUBLEMASK. Row 0 is unused, row 1
* has the stats for band 1. These are: (minimum, maximum, sum, sum^2). If the
* offset of out if 42, then it has not been inited yet and we just copy.
*/
static int
merge_mask( void *seq, void *a, void *b )
{
DOUBLEMASK *tmp = (DOUBLEMASK *) seq;
DOUBLEMASK *out = (DOUBLEMASK *) a;
double *rowi, *rowo;
int z;
/* Merge, or just copy?
*/
if( out->offset != 42 )
/* Add info from tmp.
*/
for( z = 1; z < tmp->ysize; z++ ) {
rowi = tmp->coeff + z * 6;
rowo = out->coeff + z * 6;
rowo[0] = IM_MIN( rowi[0], rowo[0] );
rowo[1] = IM_MAX( rowi[1], rowo[1] );
rowo[2] += rowi[2];
rowo[3] += rowi[3];
}
else {
/* Copy info from tmp.
*/
for( z = 1; z < tmp->ysize; z++ ) {
rowi = tmp->coeff + z * 6;
rowo = out->coeff + z * 6;
rowo[0] = rowi[0];
rowo[1] = rowi[1];
rowo[2] = rowi[2];
rowo[3] = rowi[3];
}
out->offset = 0;
}
/* Can now free tmp.
*/
im_free_dmask( tmp );
return( 0 );
}
/* Loop over region, adding information to the appropriate fields of tmp.
* We set max, min, sum, sum of squares. Our caller fills in the rest.
*/
static int
scan_fn( REGION *reg, void *seq, void *a, void *b )
{
DOUBLEMASK *tmp = (DOUBLEMASK *) seq;
Rect *r = &reg->valid;
IMAGE *im = reg->im;
int bands = im->Bands;
int le = r->left;
int ri = IM_RECT_RIGHT(r);
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int x, y, z;
/* What type? First define the loop we want to perform for all types.
* We scan lines bands times to avoid repeating band loops.
* Use temp variables of same type for min/max for faster comparisons.
* Use double to sum bands.
*/
#define non_complex_loop(TYPE) \
{ TYPE *p, *q; \
TYPE value, small, big; \
double *row; \
\
/* Have min and max been initialised? \
*/ \
if( tmp->offset == 42 ) { \
/* Init min and max for each band. \
*/ \
p = (TYPE *) IM_REGION_ADDR( reg, le, to ); \
for( z = 1; z < bands + 1; z++ ) { \
row = tmp->coeff + z * 6; \
row[0] = p[z - 1]; \
row[1] = p[z - 1]; \
} \
tmp->offset = 0; \
} \
\
for( y = to; y < bo; y++ ) { \
p = (TYPE *) IM_REGION_ADDR( reg, le, y ); \
\
for( z = 0; z < bands; z++ ) { \
q = p + z; \
row = tmp->coeff + (z + 1)*6; \
small = row[0]; \
big = row[1]; \
\
for( x = le; x < ri; x++ ) { \
value = *q; \
q += bands; \
row[2] += value;\
row[3] += (double)value*(double)value;\
if( value > big ) \
big = value; \
else if( value < small ) \
small = value;\
}\
\
row[0] = small; \
row[1] = big; \
}\
}\
}
/* Now generate code for all types.
*/
switch( im->BandFmt ) {
case IM_BANDFMT_UCHAR: non_complex_loop(unsigned char); break;
case IM_BANDFMT_CHAR: non_complex_loop(signed char); break;
case IM_BANDFMT_USHORT: non_complex_loop(unsigned short); break;
case IM_BANDFMT_SHORT: non_complex_loop(signed short); break;
case IM_BANDFMT_UINT: non_complex_loop(unsigned int); break;
case IM_BANDFMT_INT: non_complex_loop(signed int); break;
case IM_BANDFMT_DOUBLE: non_complex_loop(double); break;
case IM_BANDFMT_FLOAT: non_complex_loop(float); break;
default:
assert( 0 );
}
return( 0 );
}
/* Find the statistics of an image. Take any non-complex format. Write the
* stats to a DOUBLEMASK of size 6 by (in->Bands+1). We hold a row for each
* band, plus one row for all bands. Row n has 6 elements, which are, in
* order, (minimum, maximum, sum, sum^2, mean, deviation) for band n. Row 0 has
* the figures for all bands together.
*/
DOUBLEMASK *
im_stats( IMAGE *in )
{
DOUBLEMASK *out;
double *row, *base;
gint64 pels, vals, z;
/* Check our args.
*/
if( im_pincheck( in ) )
return( NULL );
if( im_iscomplex( in ) ) {
im_error( "im_stats", "%s", _( "bad input type" ) );
return( NULL );
}
if( in->Coding != IM_CODING_NONE ) {
im_error( "im_stats", "%s", _( "not uncoded" ) );
return( NULL );
}
/* Make output.
*/
pels = (gint64) in->Xsize * in->Ysize;
vals = pels * in->Bands;
if( !(out = make_mask( in, NULL, NULL )) )
return( NULL );
/* Loop over input, calculating min, max, sum, sum^2 for each band
* separately.
*/
if( im_iterate( in, make_mask, scan_fn, merge_mask, out, NULL ) ) {
im_free_dmask( out );
return( NULL );
}
/* Calculate mean, deviation, plus overall stats.
*/
base = out->coeff;
base[0] = base[6]; /* Init global max/min */
base[1] = base[7];
for( z = 0; z < in->Bands; z++ ) {
row = base + (z + 1) * 6;
base[0] = IM_MIN( base[0], row[0] );
base[1] = IM_MAX( base[1], row[1] );
base[2] += row[2];
base[3] += row[3];
row[4] = row[2] / pels;
row[5] = sqrt( fabs( row[3] - (row[2] * row[2] / pels) ) /
(pels - 1) );
}
base[4] = base[2] / vals;
base[5] = sqrt( fabs( base[3] - (base[2] * base[2] / vals) ) /
(vals - 1) );
return( out );
}