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/* Cored sharpen of LABQ image.
*
* Returns 0 on success and -1 on error
*
* Copyright: 1995 A. Abbood
* Author: A. Abbood
* Written on: 30/01/1995
* 15/5/95 JC
* - updated for latest 7.3 mods
* - m3 parameter removed
* - bug fixes and speed-ups
* 4/7/95 JC
* - x3 parameter added
* - xs are now double
* 6/7/95 JC
* - xs are now ys
* - better LUT generation
* 12/3/01 JC
* - uses seperable convolution for umask
* - tiny clean ups
* 23/7/01 JC
* - fix for band extract index changed
* 21/4/04
* - switched to gaussian mask and radius
* 20/11/04
* - uses extract_bands() to remove and reattach ab for slight speedup
* - accepts LabS as well as LabQ for slight speedup
* - small code tidies
* - ~15% speed up in total
* 29/11/06
* - convolve first to help region sharing
* 3/2/10
* - gtkdoc
* - cleanups
* 13/11/13
* - redo as a class
* - does any type, any number of bands
* 24/2/16
* - swap "radius" for "sigma", allows finer control
* - allow a much greater range of parameters
* - move to defaults suitable for screen output
*/
/*
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG
*/
#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 <vips/vips.h>
typedef struct _VipsSharpen {
VipsOperation parent_instance;
VipsImage *in;
VipsImage *out;
double sigma;
double x1;
double y2;
double y3;
double m1;
double m2;
/* The lut we build.
*/
int *lut;
/* We used to have a radius control.
*/
int radius;
} VipsSharpen;
typedef VipsOperationClass VipsSharpenClass;
G_DEFINE_TYPE( VipsSharpen, vips_sharpen, VIPS_TYPE_OPERATION );
static int
vips_sharpen_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion **in = (VipsRegion **) vseq;
VipsSharpen *sharpen = (VipsSharpen *) b;
VipsRect *r = &or->valid;
int *lut = sharpen->lut;
int x, y;
if( vips_reorder_prepare_many( or->im, in, r ) )
return( -1 );
VIPS_GATE_START( "vips_sharpen_generate: work" );
for( y = 0; y < r->height; y++ ) {
short *p1 = (short * restrict)
VIPS_REGION_ADDR( in[0], r->left, r->top + y );
short *p2 = (short * restrict)
VIPS_REGION_ADDR( in[1], r->left, r->top + y );
short *q = (short * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
int v1 = p1[x];
int v2 = p2[x];
/* Our LUT is -32768 - 32767. For the v1, v2
* difference to be in this range, both must be 0 -
* 32767.
*/
int diff = ((v1 & 0x7fff) - (v2 & 0x7fff));
int out;
g_assert( diff + 32768 >= 0 );
g_assert( diff + 32768 < 65536 );
out = v1 + lut[diff + 32768];
if( out < 0 )
out = 0;
if( out > 32767 )
out = 32767;
q[x] = out;
}
}
VIPS_GATE_STOP( "vips_sharpen_generate: work" );
return( 0 );
}
static int
vips_sharpen_build( VipsObject *object )
{
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
VipsSharpen *sharpen = (VipsSharpen *) object;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 7 );
VipsImage **args = (VipsImage **) vips_object_local_array( object, 2 );
VipsImage *in;
int i;
VIPS_GATE_START( "vips_sharpen_build: build" );
if( VIPS_OBJECT_CLASS( vips_sharpen_parent_class )->build( object ) )
return( -1 );
/* We used to have a radius control. If that's set but sigma isn't,
* use it to set a reasonable value for sigma.
*/
if( !vips_object_argument_isset( object, "sigma" ) &&
vips_object_argument_isset( object, "radius" ) )
sharpen->sigma = 1 + sharpen->radius / 2;
in = sharpen->in;
if( vips_colourspace( in, &t[0], VIPS_INTERPRETATION_LABS, NULL ) )
return( -1 );
in = t[0];
if( vips_check_uncoded( class->nickname, in ) ||
vips_check_bands_atleast( class->nickname, in, 3 ) ||
vips_check_format( class->nickname, in, VIPS_FORMAT_SHORT ) )
return( -1 );
/* Stop at 20% of max ... a bit mean. We always sharpen a short,
* so there's no point using a float mask.
*/
if( vips_gaussmat( &t[1], sharpen->sigma, 0.2,
"separable", TRUE,
"precision", VIPS_PRECISION_INTEGER,
NULL ) )
return( -1 );
#ifdef DEBUG
printf( "sharpen: blurring with:\n" );
vips_matrixprint( t[1], NULL );
#endif /*DEBUG*/
/* Index with the signed difference between two 0 - 32767 images.
*/
if( !(sharpen->lut = VIPS_ARRAY( object, 65536, int )) )
return( -1 );
for( i = 0; i < 65536; i++ ) {
/* Rescale to +/- 100.
*/
double v = (i - 32767) / 327.67;
double y;
if( v < -sharpen->x1 )
/* Left of -x1.
*/
y = (v + sharpen->x1) * sharpen->m2 +
-sharpen->x1 * sharpen->m1;
else if( v < sharpen->x1 )
/* Centre section.
*/
y = v * sharpen->m1;
else
/* Right of x1.
*/
y = (v - sharpen->x1) * sharpen->m2 +
sharpen->x1 * sharpen->m1;
if( y < -sharpen->y3 )
y = -sharpen->y3;
if( y > sharpen->y2 )
y = sharpen->y2;
sharpen->lut[i] = VIPS_RINT( y * 327.67 );
}
#ifdef DEBUG
{
VipsImage *mat;
mat = vips_image_new_matrix( 65536, 1 );
for( i = 0; i < 65536; i++ )
*VIPS_MATRIX( mat, i, 0 ) = sharpen->lut[i];
vips_image_write_to_file( mat, "x.v", NULL );
printf( "lut written to x.v\n" );
g_object_unref( mat );
}
#endif /*DEBUG*/
/* Extract L and the rest, convolve L.
*/
if( vips_extract_band( in, &args[0], 0, NULL ) ||
vips_extract_band( in, &t[3], 1, "n", in->Bands - 1, NULL ) ||
vips_convsep( args[0], &args[1], t[1],
"precision", VIPS_PRECISION_INTEGER,
NULL ) )
return( -1 );
/* Set demand hints. FATSTRIP is good for us, as THINSTRIP will cause
* too many recalculations on overlaps.
*/
t[5] = vips_image_new();
if( vips_image_pipeline_array( t[5],
VIPS_DEMAND_STYLE_FATSTRIP, args ) )
return( -1 );
if( vips_image_generate( t[5],
vips_start_many, vips_sharpen_generate, vips_stop_many,
args, sharpen ) )
return( -1 );
g_object_set( object, "out", vips_image_new(), NULL );
/* Reattach the rest.
*/
if( vips_bandjoin2( t[5], t[3], &t[6], NULL ) ||
vips_image_write( t[6], sharpen->out ) )
return( -1 );
VIPS_GATE_STOP( "vips_sharpen_build: build" );
return( 0 );
}
static void
vips_sharpen_class_init( VipsSharpenClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "sharpen";
object_class->description = _( "unsharp masking for print" );
object_class->build = vips_sharpen_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
VIPS_ARG_IMAGE( class, "in", 1,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsSharpen, in ) );
VIPS_ARG_IMAGE( class, "out", 2,
_( "Output" ),
_( "Output image" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsSharpen, out ) );
VIPS_ARG_DOUBLE( class, "sigma", 3,
_( "Sigma" ),
_( "Sigma of Gaussian" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, sigma ),
0.000001, 10000.0, 0.5 );
VIPS_ARG_DOUBLE( class, "x1", 5,
_( "x1" ),
_( "Flat/jaggy threshold" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, x1 ),
0, 1000000, 2.0 );
VIPS_ARG_DOUBLE( class, "y2", 6,
_( "y2" ),
_( "Maximum brightening" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, y2 ),
0, 1000000, 10 );
VIPS_ARG_DOUBLE( class, "y3", 7,
_( "y3" ),
_( "Maximum darkening" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, y3 ),
0, 1000000, 20 );
VIPS_ARG_DOUBLE( class, "m1", 8,
_( "m1" ),
_( "Slope for flat areas" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, m1 ),
0, 1000000, 0.0 );
VIPS_ARG_DOUBLE( class, "m2", 9,
_( "m2" ),
_( "Slope for jaggy areas" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, m2 ),
0, 1000000, 3.0 );
/* We used to have a radius control.
*/
VIPS_ARG_INT( class, "radius", 3,
_( "Radius" ),
_( "radius of Gaussian" ),
VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
G_STRUCT_OFFSET( VipsSharpen, radius ),
1, 100, 1 );
}
static void
vips_sharpen_init( VipsSharpen *sharpen )
{
sharpen->sigma = 0.5;
sharpen->x1 = 2.0;
sharpen->y2 = 10.0;
sharpen->y3 = 20.0;
sharpen->m1 = 0.0;
sharpen->m2 = 3.0;
}
/**
* vips_sharpen: (method)
* @in: input image
* @out: (out): output image
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @sigma: sigma of gaussian
* * @x1: flat/jaggy threshold
* * @y2: maximum amount of brightening
* * @y3: maximum amount of darkening
* * @m1: slope for flat areas
* * @m2: slope for jaggy areas
*
* Selectively sharpen the L channel of a LAB image. The input image is
* transformed to #VIPS_INTERPRETATION_LABS.
*
* The operation performs a gaussian blur and subtracts from @in to generate a
* high-frequency signal. This signal is passed through a lookup table formed
* from the five parameters and added back to @in.
*
* The lookup table is formed like this:
*
* |[
* . ^
* . y2 |- - - - - -----------
* . | /
* . | / slope m2
* . | .../
* . -x1 | ... |
* . -------------------...---------------------->
* . | ... | x1
* . |... slope m1
* . / |
* . / m2 |
* . / |
* . / |
* . / |
* . / |
* . ______/ _ _ _ _ _ _ | -y3
* . |
* ]|
*
* For screen output, we suggest the following settings (the defaults):
*
* |[
* sigma == 0.5
* x1 == 2
* y2 == 10 (don't brighten by more than 10 L*)
* y3 == 20 (can darken by up to 20 L*)
* m1 == 0 (no sharpening in flat areas)
* m2 == 3 (some sharpening in jaggy areas)
* ]|
*
* If you want more or less sharpening, we suggest you just change the
* m2 parameter.
*
* The @sigma parameter changes the width of the fringe and can be
* adjusted according to the output printing resolution. As an approximate
* guideline, use 0.5 for 4 pixels/mm (display resolution),
* 1.0 for 12 pixels/mm and 1.5 for 16 pixels/mm (300 dpi == 12
* pixels/mm). These figures refer to the image raster, not the half-tone
* resolution.
*
* See also: vips_conv().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_sharpen( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "sharpen", ap, in, out );
va_end( ap );
return( result );
}
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