169 lines
4.1 KiB
C
169 lines
4.1 KiB
C
/* Histogram-equalise an image.
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*
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* Copyright: 1991, N. Dessipris.
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*
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* Author: Nicos Dessipris
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* Written on: 27/03/1991
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* Modified on :
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* 16/6/93 J.Cupitt
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* - im_ioflag() changed to im_iocheck()
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* 24/5/95 JC
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* - ANSIfied and tidied up
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* 3/3/01 JC
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* - more cleanup
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* 23/3/10
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* - gtkdoc
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* 12/8/13
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* - redone as a class
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* 19/6/17
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* - make output format always == input format, thanks Simon
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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 <vips/vips.h>
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typedef struct _VipsHistEqual {
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VipsOperation parent_instance;
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VipsImage *in;
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VipsImage *out;
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/* -1 for all bands, or the band we scan.
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*/
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int which;
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} VipsHistEqual;
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typedef VipsOperationClass VipsHistEqualClass;
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G_DEFINE_TYPE( VipsHistEqual, vips_hist_equal, VIPS_TYPE_OPERATION );
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static int
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vips_hist_equal_build( VipsObject *object )
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{
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VipsHistEqual *equal = (VipsHistEqual *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 5 );
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g_object_set( equal, "out", vips_image_new(), NULL );
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if( VIPS_OBJECT_CLASS( vips_hist_equal_parent_class )->build( object ) )
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return( -1 );
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/* norm can return a uchar output for a ushort input if the range is
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* small, so make sure we cast back to the input type again.
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*/
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if( vips_hist_find( equal->in, &t[0],
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"band", equal->which,
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NULL ) ||
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vips_hist_cum( t[0], &t[1], NULL ) ||
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vips_hist_norm( t[1], &t[2], NULL ) ||
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vips_cast( t[2], &t[3], equal->in->BandFmt, NULL ) ||
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vips_maplut( equal->in, &t[4], t[3], NULL ) ||
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vips_image_write( t[4], equal->out ) )
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return( -1 );
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return( 0 );
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}
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static void
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vips_hist_equal_class_init( VipsHistEqualClass *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_equal";
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object_class->description = _( "histogram equalisation" );
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object_class->build = vips_hist_equal_build;
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VIPS_ARG_IMAGE( class, "in", 1,
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_( "Input" ),
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_( "Input image" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsHistEqual, in ) );
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VIPS_ARG_IMAGE( class, "out", 2,
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_( "Output" ),
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_( "Output image" ),
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VIPS_ARGUMENT_REQUIRED_OUTPUT,
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G_STRUCT_OFFSET( VipsHistEqual, out ) );
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VIPS_ARG_INT( class, "band", 110,
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_( "Band" ),
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_( "Equalise with this band" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsHistEqual, which ),
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-1, 100000, -1 );
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}
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static void
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vips_hist_equal_init( VipsHistEqual *equal )
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{
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equal->which = -1;
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}
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/**
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* vips_hist_equal: (method)
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* @in: input image
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* @out: (out): output image
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* * @band: band to equalise
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*
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* Histogram-equalise @in. Equalise using band @bandno, or if @bandno is -1,
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* equalise bands independently. The output format is always the same as the
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* input format.
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*
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* See also:
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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_equal( VipsImage *in, VipsImage **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_equal", ap, in, out );
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va_end( ap );
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return( result );
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}
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