libvips/libsrc/convolution/im_addgnoise.c

97 lines
2.4 KiB
C

/* @(#) Add gaussian noise with mean 0 and variance sigma to image
* @(#) The noise is generated by averaging 12 random numbers
* @(#) page 78 PIETGEN 1989 n = 12
* @(#) Input image is any, output is float
* @(#) If running on SYSTEM V CONSTANT should be replaced by 2**15 - 1
* @(#) Usage
* @(#)
* @(#) int im_addgnoise(imin, imout, sigma)
* @(#) IMAGE *imin, *imout;
* @(#) double sigma;
* @(#) Returns 0 on success and -1 on error
* @(#)
*
* Copyright 1990, N. Dessipris.
*
* File written on 2/12/1986
* Author : N. Dessipris
* Updated : 22/01/1991
* 1/2/95 JC
* - junked!
* - now uses partial im_gaussnoise() and partial im_add() to do the
* same job
& 1/5/01 JC
* - oops, failed for not-1-band images
*/
/*
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
#define MAX_BANDS (200)
int
im_addgnoise( IMAGE *in, IMAGE *out, double sigma )
{
IMAGE *noise[MAX_BANDS];
IMAGE *nb;
int i;
if( in->Bands > MAX_BANDS ) {
im_error( "im_addgnoise", _( "too many bands" ) );
return( -1 );
}
/* Make n-band noise image.
*/
for( i = 0; i < in->Bands; i++ )
if( !(noise[i] = im_open_local( out, "im_addgnoise:2", "p" )) ||
im_gaussnoise( noise[i], in->Xsize, in->Ysize,
0.0, sigma ) )
return( -1 );
if( !(nb = im_open_local( out, "im_addgnoise:3", "p" )) ||
im_gbandjoin( noise, out, in->Bands ) ||
im_add( in, nb, out ) )
return( -1 );
return( 0 );
}