159 lines
3.5 KiB
C
159 lines
3.5 KiB
C
/* @(#) Creates a Gaussian noisy float image with mean of 0 and variance of 1
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* @(#) by averaging 12 random numbers
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* @(#) Creates one band float image
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* @(#) page 78 PIETGEN 1989 n = 12
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* @(#) Usage
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* @(#)
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* @(#) int im_gaussnoise(image, xsize, ysize, mean, sigma)
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* @(#) IMAGE *image;
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* @(#) int xsize, ysize;
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* @(#) double mean, sigma;
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* @(#)
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* @(#) Returns 0 on success and -1 on error
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*
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* Copyright 1990, N. Dessipris.
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*
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* File written on 2/12/1986
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* Author : N. Dessipris
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* Updated : 6/6/1991
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* 21/7/93 JC
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* - im_outcheck() call added
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* 1/2/95 JC
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* - declaration for drand48() added
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* - partialised, adapting im_black()
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* 23/10/98 JC
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* - drand48() chaged to random() for poartability
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* 21/10/02 JC
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* - tries rand() if random() is not available
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* - uses RAND_MAX, d'oh
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 <stdlib.h>
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#include <vips/vips.h>
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif /*WITH_DMALLOC*/
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/* Keep parameters here.
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*/
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typedef struct {
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double mean;
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double sigma;
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} GnoiseInfo;
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/* Generate function --- just fill the region with noise. "dummy" is our
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* sequence value: we don't need one.
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*/
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/*ARGSUSED*/
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static int
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gnoise_gen( REGION *or, void *seq, void *a, void *b )
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{
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GnoiseInfo *gin = (GnoiseInfo *) a;
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int x, y, i;
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int sz = IM_REGION_N_ELEMENTS( or );
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for( y = 0; y < or->valid.height; y++ ) {
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float *q = (float *)
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IM_REGION_ADDR( or, or->valid.left, y + or->valid.top );
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for( x = 0; x < sz; x++ ) {
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double sum = 0.0;
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for( i = 0; i < 12; i++ )
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#ifdef HAVE_RANDOM
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sum += (double) random() / RAND_MAX;
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#else /*HAVE_RANDOM*/
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#ifdef HAVE_RAND
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sum += (double) rand() / RAND_MAX;
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#else /*HAVE_RAND*/
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#error "no random number generator found"
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#endif /*HAVE_RAND*/
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#endif /*HAVE_RAND*/
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q[x] = (sum - 6.0) * gin->sigma + gin->mean;
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}
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}
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return( 0 );
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}
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/* Make a one band float image of gaussian noise.
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*/
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int
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im_gaussnoise( IMAGE *out, int x, int y, double mean, double sigma )
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{
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GnoiseInfo *gin;
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/* Check parameters.
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*/
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if( x < 0 || y < 0 ) {
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im_errormsg( "im_gaussnoise: bad parameter" );
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return( -1 );
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}
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/* Check descriptor.
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*/
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if( im_poutcheck( out ) )
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return( -1 );
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/* Set fields.
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*/
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im_initdesc( out,
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x, y, 1,
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IM_BBITS_FLOAT, IM_BANDFMT_FLOAT, IM_CODING_NONE, IM_TYPE_B_W,
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1.0, 1.0, 0, 0 );
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/* Set hints - ANY is ok with us.
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*/
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if( im_demand_hint( out, IM_ANY, NULL ) )
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return( -1 );
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/* Save parameters.
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*/
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if( !(gin = IM_NEW( out, GnoiseInfo )) )
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return( -1 );
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gin->mean = mean;
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gin->sigma = sigma;
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/* Generate image.
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*/
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if( im_generate( out, NULL, gnoise_gen, NULL, gin, NULL ) )
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return( -1 );
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return( 0 );
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}
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