158 lines
4.2 KiB
C
158 lines
4.2 KiB
C
/* creates an ideal filter.
|
|
*
|
|
* 02/01/14
|
|
* - from ideal.c
|
|
*/
|
|
|
|
/*
|
|
|
|
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., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
02110-1301 USA
|
|
|
|
*/
|
|
|
|
/*
|
|
|
|
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
|
|
|
|
*/
|
|
|
|
/*
|
|
#define VIPS_DEBUG
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include <config.h>
|
|
#endif /*HAVE_CONFIG_H*/
|
|
#include <glib/gi18n-lib.h>
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
|
|
#include <vips/vips.h>
|
|
|
|
#include "pcreate.h"
|
|
#include "point.h"
|
|
#include "pmask.h"
|
|
|
|
G_DEFINE_TYPE( VipsMaskIdeal, vips_mask_ideal, VIPS_TYPE_MASK );
|
|
|
|
static double
|
|
vips_mask_ideal_point( VipsMask *mask, double dx, double dy )
|
|
{
|
|
VipsMaskIdeal *ideal = (VipsMaskIdeal *) mask;
|
|
double fc = ideal->frequency_cutoff;
|
|
|
|
double dist2 = dx * dx + dy * dy;
|
|
double fc2 = fc * fc;
|
|
|
|
return( dist2 <= fc2 ? 0.0 : 1.0 );
|
|
}
|
|
|
|
static void
|
|
vips_mask_ideal_class_init( VipsMaskIdealClass *class )
|
|
{
|
|
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
|
|
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
|
|
VipsMaskClass *mask_class = VIPS_MASK_CLASS( class );
|
|
|
|
gobject_class->set_property = vips_object_set_property;
|
|
gobject_class->get_property = vips_object_get_property;
|
|
|
|
vobject_class->nickname = "mask_ideal";
|
|
vobject_class->description = _( "make an ideal filter" );
|
|
|
|
mask_class->point = vips_mask_ideal_point;
|
|
|
|
VIPS_ARG_DOUBLE( class, "frequency_cutoff", 6,
|
|
_( "Frequency cutoff" ),
|
|
_( "Frequency cutoff" ),
|
|
VIPS_ARGUMENT_REQUIRED_INPUT,
|
|
G_STRUCT_OFFSET( VipsMaskIdeal, frequency_cutoff ),
|
|
0.0, 1000000.0, 0.5 );
|
|
|
|
}
|
|
|
|
static void
|
|
vips_mask_ideal_init( VipsMaskIdeal *ideal )
|
|
{
|
|
ideal->frequency_cutoff = 0.5;
|
|
}
|
|
|
|
/**
|
|
* vips_mask_ideal:
|
|
* @out: (out): output image
|
|
* @width: image size
|
|
* @height: image size
|
|
* @frequency_cutoff: threshold at which filter ends
|
|
* @...: %NULL-terminated list of optional named arguments
|
|
*
|
|
* Optional arguments:
|
|
*
|
|
* * @nodc: don't set the DC pixel
|
|
* * @reject: invert the filter sense
|
|
* * @optical: coordinates in optical space
|
|
* * @uchar: output a uchar image
|
|
*
|
|
* Make an ideal high- or low-pass filter, that is, one with a sharp cutoff
|
|
* positioned at @frequency_cutoff, where @frequency_cutoff is in
|
|
* the range 0 - 1.
|
|
*
|
|
* This operation creates a one-band float image of the specified size.
|
|
* The image has
|
|
* values in the range [0, 1] and is typically used for multiplying against
|
|
* frequency domain images to filter them.
|
|
* Masks are created with the DC component at (0, 0). The DC pixel always
|
|
* has the value 1.0.
|
|
*
|
|
* Set @nodc to not set the DC pixel.
|
|
*
|
|
* Set @optical to position the DC component in the centre of the image. This
|
|
* makes the mask suitable for multiplying against optical Fourier transforms.
|
|
* See vips_wrap().
|
|
*
|
|
* Set @reject to invert the sense of
|
|
* the filter. For example, low-pass becomes low-reject.
|
|
*
|
|
* Set @uchar to output an 8-bit unsigned char image rather than a
|
|
* float image. In this case, pixels are in the range [0 - 255].
|
|
*
|
|
* See also: vips_mask_ideal(), vips_mask_ideal_ring(),
|
|
* vips_mask_ideal_band(), vips_mask_butterworth(),
|
|
* vips_mask_butterworth_ring(), vips_mask_butterworth_band(),
|
|
* vips_mask_gaussian(), vips_mask_gaussian_ring(),
|
|
* vips_mask_gaussian_band().
|
|
*
|
|
* Returns: 0 on success, -1 on error
|
|
*/
|
|
int
|
|
vips_mask_ideal( VipsImage **out, int width, int height,
|
|
double frequency_cutoff, ... )
|
|
{
|
|
va_list ap;
|
|
int result;
|
|
|
|
va_start( ap, frequency_cutoff );
|
|
result = vips_call_split( "mask_ideal", ap, out, width, height,
|
|
frequency_cutoff );
|
|
va_end( ap );
|
|
|
|
return( result );
|
|
}
|