add vips_entropy()
calculates image entropy from a histogram
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@ -15,6 +15,8 @@
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- skip oversized markers in jpeg write
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- skip oversized markers in jpeg write
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- jpeg exif tags saved as name rather than title
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- jpeg exif tags saved as name rather than title
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- can now set any jpeg exif tag, not just modify existing tags
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- can now set any jpeg exif tag, not just modify existing tags
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- add vips_hist_entropy()
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- vips_log(), vips_log10() are zero-avoiding
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7/5/15 started 8.0.3
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7/5/15 started 8.0.3
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- dzsave and tif pyr write could fail for some image dimensions, thanks Jonas
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- dzsave and tif pyr write could fail for some image dimensions, thanks Jonas
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@ -14,6 +14,7 @@ libhistogram_la_SOURCES = \
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hist_local.c \
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hist_local.c \
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percent.c \
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percent.c \
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hist_ismonotonic.c \
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hist_ismonotonic.c \
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hist_entropy.c \
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stdif.c
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stdif.c
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AM_CPPFLAGS = -I${top_srcdir}/libvips/include @VIPS_CFLAGS@ @VIPS_INCLUDES@
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AM_CPPFLAGS = -I${top_srcdir}/libvips/include @VIPS_CFLAGS@ @VIPS_INCLUDES@
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@ -0,0 +1,157 @@
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/* estimate entropy
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*
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* Author: John Cupitt
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* 11/8/15
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* - from hist_ismonotonic.c
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <math.h>
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#include <vips/vips.h>
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typedef struct _VipsHistEntropy {
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VipsOperation parent_instance;
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VipsImage *in;
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double out;
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} VipsHistEntropy;
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typedef VipsOperationClass VipsHistEntropyClass;
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G_DEFINE_TYPE( VipsHistEntropy, vips_hist_entropy,
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VIPS_TYPE_OPERATION );
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static int
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vips_hist_entropy_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsHistEntropy *entropy = (VipsHistEntropy *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 4 );
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double avg;
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double sum;
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if( VIPS_OBJECT_CLASS( vips_hist_entropy_parent_class )->
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build( object ) )
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return( -1 );
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if( vips_check_hist( class->nickname, entropy->in ) )
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return( -1 );
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/* Compute:
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* norm_hist = hist / sum( hist )
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* entropy = -sum( norm_hist * log2( norm_hist ) )
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*/
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if( vips_avg( entropy->in, &avg, NULL ) )
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return( -1 );
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sum = avg * VIPS_IMAGE_N_PELS( entropy->in ) * entropy->in->Bands;
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if( vips_linear1( entropy->in, &t[0], 1.0 / sum, 0, NULL ) ||
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vips_log( t[0], &t[1], 1.0 / sum, 0, NULL ) ||
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vips_linear1( t[1], &t[2], 1.0 / log( 2.0 ), 0, NULL ) ||
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vips_multiply( t[0], t[2], &t[3], NULL ) ||
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vips_avg( t[3], &avg, NULL ) )
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return( -1 );
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g_object_set( entropy,
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"out", -avg *
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VIPS_IMAGE_N_PELS( entropy->in ) * entropy->in->Bands,
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NULL );
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return( 0 );
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}
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static void
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vips_hist_entropy_class_init( VipsHistEntropyClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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object_class->nickname = "hist_entropy";
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object_class->description = _( "estimate image entropy" );
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object_class->build = vips_hist_entropy_build;
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VIPS_ARG_IMAGE( class, "in", 1,
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_( "Input" ),
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_( "Input histogram image" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsHistEntropy, in ) );
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VIPS_ARG_DOUBLE( class, "out", 1,
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_( "Output" ),
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_( "Output value" ),
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VIPS_ARGUMENT_REQUIRED_OUTPUT,
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G_STRUCT_OFFSET( VipsHistEntropy, out ),
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-INFINITY, INFINITY, 0.0 );
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}
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static void
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vips_hist_entropy_init( VipsHistEntropy *entropy )
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{
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}
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/**
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* vips_hist_entropy:
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* @in: input histogram
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* @out: image entropy
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* @...: %NULL-terminated list of optional named arguments
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*
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* Estimate image entropy from a histogram. Entropy is calculated as:
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*
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* |[
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* -sum( p * log2( p ) )
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* ]|
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*
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* where p is histogram-value / sum-of-histogram-values.
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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vips_hist_entropy( VipsImage *in, double *out, ... )
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{
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va_list ap;
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int result;
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va_start( ap, out );
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result = vips_call_split( "hist_entropy", ap, in, out );
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va_end( ap );
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return( result );
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}
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@ -136,7 +136,7 @@ vips_hist_ismonotonic_init( VipsHistIsmonotonic *ismonotonic )
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/**
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/**
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* vips_hist_ismonotonic:
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* vips_hist_ismonotonic:
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* @in: lookup-table to test
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* @in: lookup-table to test
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* @monotonic: set non-zero if @in is monotonic
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* @out: set non-zero if @in is monotonic
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* @...: %NULL-terminated list of optional named arguments
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* @...: %NULL-terminated list of optional named arguments
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*
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*
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* Test @in for monotonicity. @out is set non-zero if @in is monotonic.
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* Test @in for monotonicity. @out is set non-zero if @in is monotonic.
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@ -144,13 +144,13 @@ vips_hist_ismonotonic_init( VipsHistIsmonotonic *ismonotonic )
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* Returns: 0 on success, -1 on error
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* Returns: 0 on success, -1 on error
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*/
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*/
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int
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int
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vips_hist_ismonotonic( VipsImage *in, gboolean *monotonic, ... )
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vips_hist_ismonotonic( VipsImage *in, gboolean *out, ... )
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{
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{
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va_list ap;
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va_list ap;
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int result;
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int result;
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va_start( ap, monotonic );
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va_start( ap, out );
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result = vips_call_split( "hist_ismonotonic", ap, in, monotonic );
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result = vips_call_split( "hist_ismonotonic", ap, in, out );
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va_end( ap );
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va_end( ap );
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return( result );
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return( result );
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@ -258,6 +258,7 @@ vips_histogram_operation_init( void )
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extern GType vips_hist_match_get_type( void );
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extern GType vips_hist_match_get_type( void );
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extern GType vips_hist_local_get_type( void );
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extern GType vips_hist_local_get_type( void );
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extern GType vips_hist_ismonotonic_get_type( void );
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extern GType vips_hist_ismonotonic_get_type( void );
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extern GType vips_hist_entropy_get_type( void );
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extern GType vips_stdif_get_type( void );
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extern GType vips_stdif_get_type( void );
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vips_maplut_get_type();
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vips_maplut_get_type();
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@ -270,4 +271,5 @@ vips_histogram_operation_init( void )
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vips_hist_match_get_type();
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vips_hist_match_get_type();
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vips_hist_local_get_type();
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vips_hist_local_get_type();
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vips_hist_ismonotonic_get_type();
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vips_hist_ismonotonic_get_type();
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vips_hist_entropy_get_type();
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}
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}
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@ -380,8 +380,10 @@ vips_stdif_init( VipsStdif *stdif )
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*
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*
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* At point (i,j) the output is given by the equation:
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* At point (i,j) the output is given by the equation:
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*
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*
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* |[
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* vout(i,j) = @a * @m0 + (1 - @a) * meanv +
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* vout(i,j) = @a * @m0 + (1 - @a) * meanv +
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* (vin(i,j) - meanv) * (@b * @s0) / (@s0 + @b * stdv)
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* (vin(i,j) - meanv) * (@b * @s0) / (@s0 + @b * stdv)
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* ]|
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*
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*
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* Values @a, @m0, @b and @s0 are entered, while meanv and stdv are the values
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* Values @a, @m0, @b and @s0 are entered, while meanv and stdv are the values
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* calculated over a moving window of size @width, @height centred on pixel
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* calculated over a moving window of size @width, @height centred on pixel
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@ -390,7 +392,9 @@ vips_stdif_init( VipsStdif *stdif )
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*
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*
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* Try:
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* Try:
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*
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*
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* |[
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* vips stdif $VIPSHOME/pics/huysum.v fred.v 0.5 128 0.5 50 11 11
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* vips stdif $VIPSHOME/pics/huysum.v fred.v 0.5 128 0.5 50 11 11
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* ]|
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*
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*
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* The operation works on one-band uchar images only, and writes a one-band
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* The operation works on one-band uchar images only, and writes a one-band
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* uchar image as its result. The output image has the same size as the
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* uchar image as its result. The output image has the same size as the
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@ -57,7 +57,9 @@ int vips_hist_match( VipsImage *in, VipsImage *ref, VipsImage **out, ... )
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int vips_hist_local( VipsImage *in, VipsImage **out,
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int vips_hist_local( VipsImage *in, VipsImage **out,
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int width, int height, ... )
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int width, int height, ... )
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__attribute__((sentinel));
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__attribute__((sentinel));
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int vips_hist_ismonotonic( VipsImage *in, gboolean *monotonic, ... )
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int vips_hist_ismonotonic( VipsImage *in, gboolean *out, ... )
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__attribute__((sentinel));
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int vips_hist_entropy( VipsImage *in, double *out, ... )
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__attribute__((sentinel));
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__attribute__((sentinel));
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#ifdef __cplusplus
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#ifdef __cplusplus
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