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hist hacking

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This commit is contained in:
John Cupitt 2010-03-25 17:07:03 +00:00
parent 05c5ae9734
commit d4517e350c
3 changed files with 128 additions and 92 deletions
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2
libvips/histograms_lut/im_lhisteq.c
View File

@ -212,7 +212,7 @@ im_lhisteq_raw( IMAGE *in, IMAGE *out, int xwin, int ywin )
* The output image is the same size as the input image. The edge pixels are
* created by copy edge pixels of the input image outwards.
*
* See also: im_heq().
* See also: im_stdif(), im_heq().
*
* Returns: 0 on success, -1 on error
*/

60
libvips/histograms_lut/im_project.c
View File

@ -1,15 +1,10 @@
/* @(#) Find the horizontal and vertical projections of an image, ie. the sum
* @(#) of pixels in each row and column. Two output images, 1xheight and
* @(#) widthx1, with the largest required bandfmt.
* @(#)
* @(#) int im_project( in, columns, rows )
* @(#) IMAGE *in;
* @(#) IMAGE *columns, *rows;
* @(#)
* @(#) Returns 0 on success and -1 on error
/* horizontal and vertical projection
*
* 20/4/06
* - from im_histgr()
* 25/3/10
* - gtkdoc
* - small celanups
*/
/*
@ -46,7 +41,6 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <vips/vips.h>
@ -133,8 +127,8 @@ project_merge( void *seq, void *a, void *b )
int hsz = in->Xsize * in->Bands;
int vsz = in->Ysize * in->Bands;
assert( sproject->hout == mproject->hout );
assert( sproject->vout == mproject->vout );
g_assert( sproject->hout == mproject->hout );
g_assert( sproject->vout == mproject->vout );
/* Add on sub-data.
*/
@ -155,7 +149,7 @@ project_merge( void *seq, void *a, void *b )
break;
default:
assert( 0 );
g_assert( 0 );
}
/* Blank out sub-project to make sure we can't add it again.
@ -238,12 +232,28 @@ project_scan( REGION *reg, void *seq, void *a, void *b )
break;
default:
assert( 0 );
g_assert( 0 );
}
return( 0 );
}
/**
* im_project:
* @in: input image
* @hout: sums of rows
* @vout: sums of columns
*
* Find the horizontal and vertical projections of an image, ie. the sum
* of every row of pixels, and the sum of every column of pixels. The output
* format is uint, int or double, depending on the input format.
*
* Non-complex images only.
*
* See also: im_histgr(), im_profile().
*
* Returns: 0 on success, -1 on error
*/
int
im_project( IMAGE *in, IMAGE *hout, IMAGE *vout )
{
@ -252,26 +262,21 @@ im_project( IMAGE *in, IMAGE *hout, IMAGE *vout )
/* Check images. PIO from in, WIO to out.
*/
if( im_pincheck( in ) || im_outcheck( hout ) || im_outcheck( vout ) )
if( im_check_uncoded( "im_project", in ) ||
im_check_noncomplex( "im_project", in ) ||
im_pincheck( in ) ||
im_outcheck( hout ) ||
im_outcheck( vout ) )
return( -1 );
if( in->Coding != IM_CODING_NONE ) {
im_error( "im_project", "%s", _( "uncoded images only" ) );
return( -1 );
}
if( vips_bandfmt_iscomplex( in->BandFmt ) ) {
im_error( "im_project", "%s", _( "non-complex images only" ) );
return( -1 );
}
/* Make the output images.
*/
if( im_cp_desc( hout, in ) || im_cp_desc( vout, in ) )
if( im_cp_desc( hout, in ) ||
im_cp_desc( vout, in ) )
return( -1 );
hout->Xsize = 1;
hout->BandFmt = project_type[in->BandFmt];
hout->Type = IM_TYPE_HISTOGRAM;
vout->Ysize = 1;
vout->BandFmt = project_type[in->BandFmt];
vout->Type = IM_TYPE_HISTOGRAM;
@ -287,7 +292,8 @@ im_project( IMAGE *in, IMAGE *hout, IMAGE *vout )
project_new_sub, project_scan, project_merge, mproject, NULL ) )
return( -1 );
if( im_setupout( hout ) || im_setupout( vout ) )
if( im_setupout( hout ) ||
im_setupout( vout ) )
return( -1 );
if( im_writeline( 0, vout, (PEL *) mproject->columns ) )

158
libvips/histograms_lut/im_stdif.c
View File

@ -1,24 +1,4 @@
/* @(#) Functions which calculates statistical differenciating according to
* @(#) the formula given in page 45 of the book "An intro to digital image
* @(#) processing" by Wayne Niblack
* @(#)
* @(#) At point (i,j) the output is given by the eqn:
* @(#)
* @(#) vout(i,j) = a*m0 +(1-a)*meanv +
* @(#) (vin(i,j) - meanv) * beta*sigma0/(sigma0+beta*stdv)
* @(#)
* @(#) Values a, m0, beta and sigma0 are entered
* @(#) meanv and stdv are the values calculated over a moving window
* @(#) xwin and ywin are the sizes of the used window
* @(#) The resultant coefficients are written as floats
* @(#) in out which has a size of in
* @(#)
* @(#) int im_stdif(in, im, alpha, mean0, beta, sigma0, xwin, ywin)
* @(#) IMAGE *in, *out;
* @(#) int xwin, ywin;
* @(#) double alpha, mean0, beta, sigma0;
* @(#)
* @(#) Returns 0 on sucess and -1 on error.
/* statistical difference
*
* Copyright: 1990, N. Dessipris.
*
@ -38,6 +18,9 @@
* 7/4/04
* - now uses im_embed() with edge stretching on the input, not
* the output
* 25/3/10
* - gtkdoc
* - small cleanups
*/
/*
@ -95,19 +78,13 @@ stdif_gen( REGION *or, void *seq, void *a, void *b )
{
REGION *ir = (REGION *) seq;
StdifInfo *inf = (StdifInfo *) b;
Rect irect;
int npel = inf->xwin * inf->ywin;
Rect *r = &or->valid;
int le = r->left;
int to = r->top;
int bo = IM_RECT_BOTTOM(r);
int ri = IM_RECT_RIGHT(r);
Rect irect;
int x, y, i, j;
int lsk;
int coff; /* Offset to move to centre of window */
int npel = inf->xwin * inf->ywin;
int centre; /* Offset to move to centre of window */
/* What part of ir do we need?
*/
@ -119,16 +96,13 @@ stdif_gen( REGION *or, void *seq, void *a, void *b )
return( -1 );
lsk = IM_REGION_LSKIP( ir );
coff = lsk * (inf->ywin/2) + inf->xwin/2;
centre = lsk * (inf->ywin / 2) + inf->xwin / 2;
for( y = to; y < bo; y++ ) {
for( y = 0; y < r->height; y++ ) {
/* Get input and output pointers for this line.
*/
PEL *p = (PEL *) IM_REGION_ADDR( ir, le, y );
PEL *q = (PEL *) IM_REGION_ADDR( or, le, y );
PEL *p1, *p2;
int sum = 0;
int sum2 = 0;
PEL *p = (PEL *) IM_REGION_ADDR( ir, r->left, r->top + y );
PEL *q = (PEL *) IM_REGION_ADDR( or, r->left, r->top + y );
/* Precompute some factors.
*/
@ -136,43 +110,55 @@ stdif_gen( REGION *or, void *seq, void *a, void *b )
double f2 = 1.0 - inf->a;
double f3 = inf->b * inf->s0;
PEL *p1;
int sum;
int sum2;
/* Find sum, sum of squares for the start of this line.
*/
for( p1 = p, j = 0; j < inf->ywin; j++, p1 += lsk )
for( p2 = p1, i = 0; i < inf->xwin; i++, p2++ ) {
int t = *p2;
sum = 0;
sum2 = 0;
p1 = p;
for( j = 0; j < inf->ywin; j++ ) {
for( i = 0; i < inf->xwin; i++ ) {
int t = p1[i];
sum += t;
sum2 += t * t;
}
p1 += lsk;
}
/* Loop for output pels.
*/
for( x = le; x < ri; x++, p++ ) {
for( x = 0; x < r->width; x++ ) {
/* Find stats.
*/
double mean = (double)sum / npel;
double var = (double)sum2 / npel - (mean * mean);
double mean = (double) sum / npel;
double var = (double) sum2 / npel - (mean * mean);
double sig = sqrt( var );
/* Transform.
*/
double res = f1 + f2*mean + ((double) p[coff] - mean) *
(f3 / (inf->s0 + inf->b*sig));
double res = f1 + f2 * mean +
((double) p[centre] - mean) *
(f3 / (inf->s0 + inf->b * sig));
/* And write.
*/
if( res < 0.0 )
*q++ = 0;
q[x] = 0;
else if( res >= 256.0 )
*q++ = 255;
q[x] = 255;
else
*q++ = res + 0.5;
q[x] = res + 0.5;
/* Adapt sums - remove the pels from the left hand
* column, add in pels for a new right-hand column.
*/
for( p1 = p, j = 0; j < inf->ywin; j++, p1 += lsk ) {
p1 = p;
for( j = 0; j < inf->ywin; j++ ) {
int t1 = p1[0];
int t2 = p1[inf->xwin];
@ -181,7 +167,11 @@ stdif_gen( REGION *or, void *seq, void *a, void *b )
sum += t2;
sum2 += t2 * t2;
p1 += lsk;
}
p += 1;
}
}
@ -195,23 +185,26 @@ im_stdif_raw( IMAGE *in, IMAGE *out,
{
StdifInfo *inf;
if( xwin > in->Xsize ||
ywin > in->Ysize ) {
im_error( "im_stdif", "%s", _( "window too large" ) );
return( -1 );
}
if( xwin <= 0 ||
ywin <= 0 ) {
im_error( "im_lhisteq", "%s", _( "window too small" ) );
return( -1 );
}
if( m0 < 0 || m0 > 255 || a < 0 || a > 1.0 || b < 0 || b > 2 ||
s0 < 0 || s0 > 255 ) {
im_error( "im_stdif", "%s", _( "parameters out of range" ) );
return( -1 );
}
if( im_piocheck( in, out ) )
if( im_check_format( "im_stdif", in, IM_BANDFMT_UCHAR ) ||
im_check_uncoded( "im_stdif", in ) ||
im_check_mono( "im_stdif", in ) ||
im_piocheck( in, out ) )
return( -1 );
if( in->BandFmt != IM_BANDFMT_UCHAR ||
in->Bands != 1 || in->Coding != IM_CODING_NONE ) {
im_error( "im_stdif", "%s",
_( "one band uchar uncoded only" ) );
return( -1 );
}
if( xwin > in->Xsize || ywin > in->Ysize ) {
im_error( "im_stdif", "%s", _( "window too large" ) );
return( -1 );
}
if( im_cp_desc( out, in ) )
return( -1 );
out->Xsize -= xwin;
@ -243,16 +236,53 @@ im_stdif_raw( IMAGE *in, IMAGE *out,
return( 0 );
}
/* The above, with a border to make out the same size as in.
/**
* im_stdif:
* @in: input image
* @out: output image
* @a: weight of new mean
* @m0: target mean
* @b: weight of new deviation
* @s0:target deviation
* @xwin: width of region
* @hwin: height of region
*
* im_stdif() preforms statistical differencing according to the formula
* given in page 45 of the book "An Introduction to Digital Image
* Processing" by Wayne Niblack. This transformation emphasises the way in
* which a pel differs statistically from its neighbours. It is useful for
* enhancing low-contrast images with lots of detail, such as X-ray plates.
*
* At point (i,j) the output is given by the equation:
*
* vout(i,j) = @a * @m0 + (1 - @a) * meanv +
* (vin(i,j) - meanv) * (@b * @s0) / (@s0 + @b * stdv)
*
* Values @a, @m0, @b and @s0 are entered, while meanv and stdv are the values
* calculated over a moving window of size @xwin, @ywin centred on pixel (i,j).
* @m0 is the new mean, @a is the weight given to it. @s0 is the new standard
* deviation, @b is the weight given to it.
*
* Try:
*
* vips im_stdif $VIPSHOME/pics/huysum.v fred.v 0.5 128 0.5 50 11 11
*
* The operation works on one-band uchar images only, and writes a one-band
* uchar image as its result. The output image has the same size as the
* input.
*
* See also: im_lhisteq().
*
* Returns: 0 on success, -1 on error
*/
int
im_stdif( IMAGE *in, IMAGE *out,
double a, double m0, double b, double s0,
int xwin, int ywin )
{
IMAGE *t1 = im_open_local( out, "im_stdif:1", "p" );
IMAGE *t1;
if( !t1 ||
if( !(t1 = im_open_local( out, "im_stdif:1", "p" )) ||
im_embed( in, t1, 1, xwin / 2, ywin / 2,
in->Xsize + xwin - 1,
in->Ysize + ywin - 1 ) ||