161 lines
3.7 KiB
C
161 lines
3.7 KiB
C
/* hough transform for lines
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*
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* 7/3/14
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* - from hist_find.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 <string.h>
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#include <vips/vips.h>
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#include "statistic.h"
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#include "hough.h"
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typedef struct _VipsHoughLine {
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VipsHough parent_instance;
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/* LUT for this transform.
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*/
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double *sin;
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} VipsHoughLine;
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typedef VipsHoughClass VipsHoughLineClass;
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G_DEFINE_TYPE( VipsHoughLine, vips_hough_line, VIPS_TYPE_HOUGH );
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static int
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vips_hough_line_build( VipsObject *object )
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{
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VipsHough *hough = (VipsHough *) object;
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VipsHoughLine *hough_line = (VipsHoughLine *) object;
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int i;
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if( !(hough_line->sin = VIPS_ARRAY( object, hough->width, double )) )
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return( -1 );
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for( i = 0; i < hough->width; i++ )
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hough_line->sin[i] = sin( 2 * VIPS_PI * i / hough->width );
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if( VIPS_OBJECT_CLASS( vips_hough_line_parent_class )->build( object ) )
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return( -1 );
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return( 0 );
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}
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static int
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vips_hough_line_init_accumulator( VipsHough *hough, VipsImage *accumulator )
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{
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vips_image_init_fields( accumulator,
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hough->width, hough->height, 1,
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VIPS_FORMAT_UINT, VIPS_CODING_NONE,
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VIPS_INTERPRETATION_MATRIX,
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1.0, 1.0 );
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return( 0 );
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}
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/* Cast votes for all lines passing through x, y.
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*/
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static void
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vips_hough_line_vote( VipsHough *hough, VipsImage *accumulator, int x, int y )
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{
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VipsHoughLine *hough_line = (VipsHoughLine *) hough;
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VipsStatistic *statistic = (VipsStatistic *) hough;
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double xd = (double) x / statistic->ready->Xsize;
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double yd = (double) y / statistic->ready->Ysize;
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int i;
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for( i = 0; i < hough->width; i++ ) {
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int i90 = (i + hough->width / 4) % hough->width;
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double r = xd * hough_line->sin[i90] + yd * hough_line->sin[i];
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int ri = hough->height * r;
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if( ri >= 0 &&
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ri < hough->height )
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*VIPS_IMAGE_ADDR( accumulator, i, ri ) += 1;
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}
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}
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static void
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vips_hough_line_class_init( VipsHoughClass *class )
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{
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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VipsHoughClass *hclass = (VipsHoughClass *) class;
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object_class->nickname = "hough_line";
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object_class->description = _( "find hough line transform" );
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object_class->build = vips_hough_line_build;
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hclass->init_accumulator = vips_hough_line_init_accumulator;
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hclass->vote = vips_hough_line_vote;
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}
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static void
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vips_hough_line_init( VipsHoughLine *hough_line )
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{
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}
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/**
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* vips_hough_line:
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* @in: input image
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* @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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* @width: horizontal size of parameter space
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* @height: vertical size of parameter space
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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_hough_line( 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( "hough_line", ap, in, out );
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va_end( ap );
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return( result );
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}
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