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any number of bands for hist_local

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This commit is contained in:
John Cupitt 2013-09-10 17:57:10 +01:00
parent 05bab10fb8
commit f1c3e1a434
2 changed files with 104 additions and 36 deletions
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1
ChangeLog
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@ -6,6 +6,7 @@
im_gammacorrect(), im_histgr(), im_histcum(), im_histnorm(), im_heq(),
im_histnD(), im_histindexed(), im_histspec(), im_invertlut(), im_lhisteq()
as classes
- vips_hist_local() does any number of bands
- thin vips8 wrapper for im_histplot()
- added vips_error_freeze() / vips_error_thaw()
- used freeze() / thaw() to stop file format sniffers logging spurious errors

139
libvips/histogram/hist_local.c
View File

@ -19,6 +19,8 @@
* - small cleanups
* 5/9/13
* - redo as a class
* 9/9/13
* - any number of bands
*/
/*
@ -74,13 +76,72 @@ typedef VipsOperationClass VipsHistLocalClass;
G_DEFINE_TYPE( VipsHistLocal, vips_hist_local, VIPS_TYPE_OPERATION );
/* Our sequence value: the region this sequence is using, and local stats.
*/
typedef struct {
VipsRegion *ir; /* Input region */
/* A 256-element hist for evry band.
*/
unsigned int **hist;
} VipsHistLocalSequence;
static int
vips_hist_local_gen( VipsRegion *or,
void *seq, void *a, void *b, gboolean *stop )
vips_hist_local_stop( void *vseq, void *a, void *b )
{
VipsRegion *ir = (VipsRegion *) seq;
VipsHistLocalSequence *seq = (VipsHistLocalSequence *) vseq;
VipsImage *in = (VipsImage *) a;
VIPS_UNREF( seq->ir );
if( seq->hist ) {
int i;
for( i = 0; i < in->Bands; i++ )
VIPS_FREE( seq->hist[i] );
VIPS_FREE( seq->hist );
}
VIPS_FREE( seq );
return( 0 );
}
static void *
vips_hist_local_start( VipsImage *out, void *a, void *b )
{
VipsImage *in = (VipsImage *) a;
VipsHistLocalSequence *seq;
int i;
if( !(seq = VIPS_NEW( NULL, VipsHistLocalSequence )) )
return( NULL );
seq->ir = NULL;
seq->hist = NULL;
if( !(seq->ir = vips_region_new( in )) ||
!(seq->hist = VIPS_ARRAY( NULL, in->Bands, unsigned int * )) ) {
vips_hist_local_stop( seq, NULL, NULL );
return( NULL );
}
for( i = 0; i < in->Bands; i++ )
if( !(seq->hist[i] = VIPS_ARRAY( NULL, 256, unsigned int )) ) {
vips_hist_local_stop( seq, NULL, NULL );
return( NULL );
}
return( seq );
}
static int
vips_hist_local_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsHistLocalSequence *seq = (VipsHistLocalSequence *) vseq;
VipsImage *in = (VipsImage *) a;
const VipsHistLocal *local = (VipsHistLocal *) b;
VipsRect *r = &or->valid;
int bands = in->Bands;
VipsRect irect;
int y;
@ -93,29 +154,31 @@ vips_hist_local_gen( VipsRegion *or,
irect.top = r->top;
irect.width = r->width + local->width;
irect.height = r->height + local->height;
if( vips_region_prepare( ir, &irect ) )
if( vips_region_prepare( seq->ir, &irect ) )
return( -1 );
lsk = VIPS_REGION_LSKIP( ir );
centre = lsk * (local->height / 2) + local->width / 2;
lsk = VIPS_REGION_LSKIP( seq->ir );
centre = lsk * (local->height / 2) + bands * local->width / 2;
for( y = 0; y < r->height; y++ ) {
/* Get input and output pointers for this line.
*/
VipsPel *p = VIPS_REGION_ADDR( ir, r->left, r->top + y );
VipsPel *p = VIPS_REGION_ADDR( seq->ir, r->left, r->top + y );
VipsPel *q = VIPS_REGION_ADDR( or, r->left, r->top + y );
VipsPel *p1;
int hist[256];
int x, i, j;
int x, i, j, b;
/* Find histogram for start of this line.
*/
memset( hist, 0, 256 * sizeof( int ) );
for( b = 0; b < bands; b++ )
memset( seq->hist[b], 0, 256 * sizeof( unsigned int ) );
p1 = p;
for( j = 0; j < local->height; j++ ) {
for( i = 0; i < local->width; i++ )
hist[p1[i]] += 1;
i = 0;
for( x = 0; x < local->width; x++ )
for( b = 0; b < bands; b++ )
seq->hist[b][p1[i++]] += 1;
p1 += lsk;
}
@ -123,30 +186,34 @@ vips_hist_local_gen( VipsRegion *or,
/* Loop for output pels.
*/
for( x = 0; x < r->width; x++ ) {
/* Sum histogram up to current pel.
*/
int target = p[centre];
int sum;
for( b = 0; b < bands; b++ ) {
/* Sum histogram up to current pel.
*/
unsigned int *hist = seq->hist[b];
int target = p[centre];
int sum;
sum = 0;
for( i = 0; i < target; i++ )
sum += hist[i];
sum = 0;
for( i = 0; i < target; i++ )
sum += hist[i];
q[x] = 256 * sum / (local->width * local->height);
*q++ = 256 * sum /
(local->width * local->height);
/* Adapt histogram --- remove the pels from the left
* hand column, add in pels for a new right-hand
* column.
*/
p1 = p;
for( j = 0; j < local->height; j++ ) {
hist[p1[0]] -= 1;
hist[p1[local->width]] += 1;
/* Adapt histogram --- remove the pels from
* the left hand column, add in pels for a
* new right-hand column.
*/
p1 = p;
for( j = 0; j < local->height; j++ ) {
hist[p1[0]] -= 1;
hist[p1[bands * local->width]] += 1;
p1 += lsk;
p1 += lsk;
}
p += 1;
}
p += 1;
}
}
@ -167,8 +234,7 @@ vips_hist_local_build( VipsObject *object )
in = local->in;
if( vips_check_mono( class->nickname, in ) ||
vips_check_uncoded( class->nickname, in ) ||
if( vips_check_uncoded( class->nickname, in ) ||
vips_check_format( class->nickname, in, VIPS_FORMAT_UCHAR ) )
return( -1 );
@ -207,7 +273,9 @@ vips_hist_local_build( VipsObject *object )
VIPS_DEMAND_STYLE_FATSTRIP, in, NULL );
if( vips_image_generate( local->out,
vips_start_one, vips_hist_local_gen, vips_stop_one,
vips_hist_local_start,
vips_hist_local_generate,
vips_hist_local_stop,
in, local ) )
return( -1 );
@ -271,8 +339,7 @@ vips_hist_local_init( VipsHistLocal *local )
* @...: %NULL-terminated list of optional named arguments
*
* Performs local histogram equalisation on @in using a
* window of size @xwin by @ywin centered on the input pixel. Works only on
* monochrome images.
* window of size @xwin by @ywin centered on the input pixel.
*
* 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.