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cleanups ready for merge

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This commit is contained in:
John Cupitt 2018-03-17 18:13:43 +00:00
parent 81a7fb92eb
commit b4181054b2
2 changed files with 0 additions and 1060 deletions
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388
libvips/convolution/angle_interpolate_canny.c
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@ -1,388 +0,0 @@
/* Canny edge detector
*
* 2/2/18
* - from vips_canny()
*/
/*
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 DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vips/vips.h>
typedef struct _VipsCanny {
VipsOperation parent_instance;
VipsImage *in;
VipsImage *out;
gdouble sigma;
/* Need an image vector for start_many.
*/
VipsImage *args[3];
} VipsCanny;
typedef VipsOperationClass VipsCannyClass;
G_DEFINE_TYPE( VipsCanny, vips_canny, VIPS_TYPE_OPERATION );
static int
vips_canny_polar_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion **in = (VipsRegion **) vseq;
VipsRect *r = &or->valid;
VipsImage *Gx = in[0]->im;
int x, y, band;
if( vips_reorder_prepare_many( or->im, in, r ) )
return( -1 );
for( y = 0; y < r->height; y++ ) {
VipsPel *p1 = (VipsPel * restrict)
VIPS_REGION_ADDR( in[0], r->left, r->top + y );
VipsPel *p2 = (VipsPel * restrict)
VIPS_REGION_ADDR( in[1], r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
for( band = 0; band < Gx->Bands; band++ ) {
int x = p1[band] - 128;
int y = p2[band] - 128;
/* Faster than hypot() for int args. Scale down
* or we'll clip on very hard edgaes.
*
* Code theta as 0 - 255 for 0 - 360.
*/
q[0] = 0.5 * sqrt( x * x + y * y );
q[1] = 255.0 * atan2( x, y ) / (2 * VIPS_PI);
q += 2;
}
p1 += Gx->Bands;
p2 += Gx->Bands;
}
}
return( 0 );
}
/* Calculate G/theta from Gx/Gy -- rather like rect -> polar, except that we
* code theta as 0 - 255 for 0 - 360 degrees. Scale G down by 0.5 so that we
* don't clip on hard edges.
*
* For a white disc on a black background, the top edge will be 128, right 64,
* bottom 255/0, left 192.
*/
static int
vips_canny_polar( VipsImage **args, VipsImage **out )
{
*out = vips_image_new();
if( vips_image_pipeline_array( *out,
VIPS_DEMAND_STYLE_THINSTRIP, args ) )
return( -1 );
(*out)->Bands *= 2;
if( vips_image_generate( *out,
vips_start_many, vips_canny_polar_generate, vips_stop_many,
args, NULL ) )
return( -1 );
return( 0 );
}
static int
vips_canny_nonmax_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion *in = (VipsRegion *) vseq;
VipsRect *r = &or->valid;
VipsImage *im = in->im;
int out_bands = or->im->Bands;
VipsRect rect;
int x, y, band;
int lsk;
int psk;
/* For each of the 256 angles, the offsets to the four neighbours we
* fetch, and the two weights we use.
*/
int offset_lowa[256];
int offset_lowb[256];
int offset_higha[256];
int offset_highb[256];
int weighta[256];
int weightb[256];
rect = *r;
rect.width += 2;
rect.height += 2;
if( vips_region_prepare( in, &rect ) )
return( -1 );
lsk = VIPS_REGION_LSKIP( in );
psk = VIPS_IMAGE_SIZEOF_PEL( im );
for( angle = 0; angle < 256; angle++ ) {
/* For a white disc on a black bg, angles run anti-clockwise
* from 0 at the bottom.
*/
}
/* For each of the four directions, the offset to get to that pixel
* from the top-left of our 3x3. offseta is the left/up direction, or
* the lower memory address.
*/
offseta[0] = psk;
offsetb[0] = psk + 2 * lsk;
offseta[1] = 2 * psk;
offsetb[1] = 2 * lsk;
offseta[2] = lsk;
offsetb[2] = 2 * psk + lsk;
offseta[3] = 0;
offsetb[3] = 2 * psk + 2 * lsk;
for( y = 0; y < r->height; y++ ) {
VipsPel *p = (VipsPel * restrict)
VIPS_REGION_ADDR( in, r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
for( band = 0; band < out_bands; band++ ) {
int G = p[lsk + psk];
int theta = p[lsk + psk + 1];
VipsPel low = p[offseta[theta]];
VipsPel high = p[offsetb[theta]];
/* Set G to 0 if it's not the local maxima in
* the direction of the gradient. If G is equal
* to the low side, also zero, so wide edges
* with equal gradient move (arbitarilly) left
* and up.
*/
if( G <= low ||
G < high )
G = 0;
q[band] = G;
p += 2;
}
q += out_bands;
}
}
return( 0 );
}
/* Remove non-maximal edges. At each point, compare the G to the G in either
* direction and 0 it if it's not the largest.
*/
static int
vips_canny_nonmax( VipsImage *in, VipsImage **out )
{
*out = vips_image_new();
if( vips_image_pipelinev( *out,
VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
return( -1 );
(*out)->Bands /= 2;
(*out)->Xsize -= 2;
(*out)->Ysize -= 2;
if( vips_image_generate( *out,
vips_start_one, vips_canny_nonmax_generate, vips_stop_one,
in, NULL ) )
return( -1 );
return( 0 );
}
static int
vips_canny_build( VipsObject *object )
{
VipsCanny *canny = (VipsCanny *) object;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 20 );
VipsImage *in;
VipsImage *Gx;
VipsImage *Gy;
if( VIPS_OBJECT_CLASS( vips_canny_parent_class )->build( object ) )
return( -1 );
in = canny->in;
if( vips_gaussblur( in, &t[0], canny->sigma, NULL ) )
return( -1 );
in = t[0];
/* Separated Sobel gives Gx / Gy. Aim for vector path. Scale down by 2
* to try to avoid clipping.
*/
t[1] = vips_image_new_matrixv( 1, 3, 1.0, 2.0, 1.0 );
vips_image_set_double( t[1], "scale", 2.0 );
t[2] = vips_image_new_matrixv( 3, 1, 1.0, 0.0, -1.0 );
vips_image_set_double( t[2], "offset", 128.0 );
if( vips_conv( in, &t[3], t[1],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ||
vips_conv( t[3], &t[4], t[2],
"precision", VIPS_PRECISION_INTEGER,
NULL ) )
return( -1 );
Gx = t[4];
t[5] = vips_image_new_matrixv( 3, 1, 1.0, 2.0, 1.0 );
vips_image_set_double( t[5], "scale", 2.0 );
t[6] = vips_image_new_matrixv( 1, 3, 1.0, 0.0, -1.0 );
vips_image_set_double( t[6], "offset", 128.0 );
if( vips_conv( in, &t[7], t[5],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ||
vips_conv( t[7], &t[8], t[6],
"precision", VIPS_PRECISION_INTEGER,
NULL ) )
return( -1 );
Gy = t[8];
/* Form (G, theta), with theta coded.
*/
canny->args[0] = Gx;
canny->args[1] = Gy;
canny->args[2] = NULL;
if( vips_canny_polar( canny->args, &t[9] ) )
return( -1 );
in = t[9];
/* Expand by two pixels all around, then thin.
if( vips_embed( in, &t[10], 1, 1, in->Xsize + 2, in->Ysize + 2,
"extend", VIPS_EXTEND_COPY,
NULL ) ||
vips_canny_nonmax( t[10], &t[11] ) )
return( -1 );
in = t[11];
*/
g_object_set( object, "out", vips_image_new(), NULL );
if( vips_image_write( in, canny->out ) )
return( -1 );
return( 0 );
}
static void
vips_canny_class_init( VipsCannyClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "canny";
object_class->description = _( "gaussian blur" );
object_class->build = vips_canny_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
VIPS_ARG_IMAGE( class, "in", 1,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsCanny, in ) );
VIPS_ARG_IMAGE( class, "out", 2,
_( "Output" ),
_( "Output image" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsCanny, out ) );
VIPS_ARG_DOUBLE( class, "sigma", 10,
_( "Sigma" ),
_( "Sigma of Gaussian" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsCanny, sigma ),
0.01, 1000, 1.4 );
}
static void
vips_canny_init( VipsCanny *canny )
{
canny->sigma = 1.4;
}
/**
* vips_canny: (method)
* @in: input image
* @out: (out): output image
* @sigma: how large a mask to use
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @sigma: %gdouble, sigma for gaussian blur
*
* See also: vips_gaussblur().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_canny( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "canny", ap, in, out );
va_end( ap );
return( result );
}

672
libvips/convolution/strong_edge.c
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@ -1,672 +0,0 @@
/* Canny edge detector
*
* 2/2/18
* - from vips_canny()
*/
/*
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
*/
/* TODO
* - add autothreshold with otsu's method
* - support other image types
*
* - leave blob analysis to a separate pass
*/
/*
#define DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vips/vips.h>
typedef struct _VipsCanny {
VipsOperation parent_instance;
VipsImage *in;
VipsImage *out;
double sigma;
gboolean interpolate;
double low;
double high;
/* Need an image vector for start_many.
*/
VipsImage *args[3];
} VipsCanny;
typedef VipsOperationClass VipsCannyClass;
G_DEFINE_TYPE( VipsCanny, vips_canny, VIPS_TYPE_OPERATION );
/* Simple 2x2 -1/+1 difference.
*/
static int
vips_canny_gradient_simple( VipsImage *in, VipsImage **Gx, VipsImage **Gy )
{
VipsImage *scope;
VipsImage **t;
scope = vips_image_new();
t = (VipsImage **) vips_object_local_array( (VipsObject *) scope, 20 );
t[1] = vips_image_new_matrixv( 2, 2,
-1.0, 1.0,
-1.0, 1.0 );
vips_image_set_double( t[1], "offset", 128.0 );
if( vips_conv( in, Gx, t[1],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ) {
g_object_unref( scope );
return( -1 );
}
t[5] = vips_image_new_matrixv( 2, 2,
-1.0, -1.0,
1.0, 1.0 );
vips_image_set_double( t[5], "offset", 128.0 );
if( vips_conv( in, Gy, t[5],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ) {
g_object_unref( scope );
return( -1 );
}
g_object_unref( scope );
return( 0 );
}
/* LUT for calculating atan2() with +/- 4 bits of precision in each axis.
*/
static VipsPel vips_canny_polar_atan2[256];
static int
vips_canny_polar_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion **in = (VipsRegion **) vseq;
VipsRect *r = &or->valid;
VipsImage *Gx = in[0]->im;
int x, y, band;
if( vips_reorder_prepare_many( or->im, in, r ) )
return( -1 );
for( y = 0; y < r->height; y++ ) {
VipsPel *p1 = (VipsPel * restrict)
VIPS_REGION_ADDR( in[0], r->left, r->top + y );
VipsPel *p2 = (VipsPel * restrict)
VIPS_REGION_ADDR( in[1], r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
for( band = 0; band < Gx->Bands; band++ ) {
int gx = p1[band] - 128;
int gy = p2[band] - 128;
/* gx/gy are -128 to +127, we need -8 to +7
* for the atan2 LUT.
*/
int i = ((gx >> 4) & 0xf) | (gy & 0xf0);
/* We should calculate
* 0.5 * sqrt( x * x + y * y )
* ie. length of hypot, scaled down to avoid
* clipping. We are only interested in relative
* magnitude, so we can skip the sqrt and just
* shift down 9 bits.
*
* Try "256 * (VIPS_DEG( atan2( gx, gy ) ) +
* 360) / 360;" to test LUT.
*/
q[0] = (gx * gx + gy * gy + 256) >> 9;
q[1] = vips_canny_polar_atan2[i];
q += 2;
}
p1 += Gx->Bands;
p2 += Gx->Bands;
}
}
return( 0 );
}
static void *
vips_atan2_init( void *null )
{
int i;
for( i = 0; i < 256; i++ ) {
/* Use the bottom 4 bits for x, the top 4 for y. The double
* shift does sign extension, assuming 2s complement.
*/
int bits = sizeof( int ) * 8 - 4;
int x = ((i & 0xf) << bits) >> bits;
int y = ((i >> 4) & 0x0f) << bits >> bits;
double theta = VIPS_DEG( atan2( x, y ) ) + 360;
vips_canny_polar_atan2[i] = 256 * theta / 360;
}
return( NULL );
}
/* Calculate G/theta from Gx/Gy -- rather like rect -> polar, except that we
* code theta as below. Scale G down by 0.5 so that we don't clip on hard
* edges.
*
* For a white disc on a black background, theta is 0 at the bottom, 64 on the
* right, 128 at the top and 192 on the left edge.
*/
static int
vips_canny_polar( VipsImage **args, VipsImage **out )
{
static GOnce once = G_ONCE_INIT;
g_once( &once, (GThreadFunc) vips_atan2_init, NULL );
*out = vips_image_new();
if( vips_image_pipeline_array( *out,
VIPS_DEMAND_STYLE_THINSTRIP, args ) )
return( -1 );
(*out)->Bands *= 2;
if( vips_image_generate( *out,
vips_start_many, vips_canny_polar_generate, vips_stop_many,
args, NULL ) )
return( -1 );
return( 0 );
}
static int
vips_canny_nonmax_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion *in = (VipsRegion *) vseq;
VipsRect *r = &or->valid;
VipsImage *im = in->im;
int out_bands = or->im->Bands;
VipsRect rect;
int x, y, band;
int lsk;
int psk;
int offseta[4];
int offsetb[4];
rect = *r;
rect.width += 2;
rect.height += 2;
if( vips_region_prepare( in, &rect ) )
return( -1 );
lsk = VIPS_REGION_LSKIP( in );
psk = VIPS_IMAGE_SIZEOF_PEL( im );
/* For each of the four directions, the offset to get to that pixel
* from the top-left of our 3x3. offseta is the left/up direction, or
* the lower memory address.
*
* 1 | 0 | 3
* --+---+--
* 2 | X | 2
* --+---+--
* 3 | 0 | 1
*/
offseta[0] = psk;
offsetb[0] = psk + 2 * lsk;
offseta[1] = 0;
offsetb[1] = 2 * psk + 2 * lsk;
offseta[2] = lsk;
offsetb[2] = 2 * psk + lsk;
offseta[3] = 2 * psk;
offsetb[3] = 2 * lsk;
for( y = 0; y < r->height; y++ ) {
VipsPel *p = (VipsPel * restrict)
VIPS_REGION_ADDR( in, r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
for( band = 0; band < out_bands; band++ ) {
int G = p[lsk + psk];
int theta = p[lsk + psk + 1];
int a = ((theta + 16) / 32) & 0x3;
VipsPel low = p[offseta[a]];
VipsPel high = p[offsetb[a]];
/* Set G to 0 if it's not the local maxima in
* the direction of the gradient. If G is equal
* to the low side, also zero, so wide edges
* with equal gradient move (arbitarilly) left
* and up.
*/
if( G <= low ||
G < high )
G = 0;
q[band] = G;
p += 2;
}
q += out_bands;
}
}
return( 0 );
}
/* Remove non-maximal edges. At each point, compare the G to the G in either
* direction and 0 it if it's not the largest.
*/
static int
vips_canny_nonmax( VipsImage *in, VipsImage **out )
{
*out = vips_image_new();
if( vips_image_pipelinev( *out,
VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
return( -1 );
(*out)->Bands /= 2;
(*out)->Xsize -= 2;
(*out)->Ysize -= 2;
if( vips_image_generate( *out,
vips_start_one, vips_canny_nonmax_generate, vips_stop_one,
in, NULL ) )
return( -1 );
return( 0 );
}
static int
vips_canny_nonmaxi_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion *in = (VipsRegion *) vseq;
VipsRect *r = &or->valid;
VipsImage *im = in->im;
int out_bands = or->im->Bands;
VipsRect rect;
int x, y, band;
int lsk;
int psk;
int offset[8];
rect = *r;
rect.width += 2;
rect.height += 2;
if( vips_region_prepare( in, &rect ) )
return( -1 );
lsk = VIPS_REGION_LSKIP( in );
psk = VIPS_IMAGE_SIZEOF_PEL( im );
/* For each of the 8 directions, the offset to get to that pixel from
* the top-left of the 3x3.
*
* 5 | 4 | 3
* --+---+--
* 6 | X | 2
* --+---+--
* 7 | 0 | 1
*/
offset[0] = psk + 2 * lsk;
offset[1] = 2 * psk + 2 * lsk;
offset[2] = 2 * psk + lsk;
offset[3] = 2 * psk;
offset[4] = psk;
offset[5] = 0;
offset[6] = lsk;
offset[7] = 2 * lsk;
for( y = 0; y < r->height; y++ ) {
VipsPel *p = (VipsPel * restrict)
VIPS_REGION_ADDR( in, r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < r->width; x++ ) {
for( band = 0; band < out_bands; band++ ) {
int G = p[lsk + psk];
int theta = p[lsk + psk + 1];
int low_theta = (theta / 32) & 0x7;
int high_theta = (low_theta + 1) & 0x7;
int residual = theta - low_theta * 32;
int lowa = p[offset[low_theta]];
int lowb = p[offset[high_theta]];
int low = (lowa * (32 - residual) +
lowb * residual) / 32;
int higha = p[offset[(low_theta + 4) & 0x7]];
int highb = p[offset[(high_theta + 4) & 0x7]];
int high = (higha * (32 - residual) +
highb * residual) / 32;
#ifdef DEBUG
if( G > 0 ) {
int i, j;
printf( "Gradient:\n" );
for( j = 0; j < 3; j++ ) {
for( i = 0; i < 3; i++ )
printf( "%3d ", p[j * lsk + i * psk] );
printf("\n");
}
printf( "Theta:\n" );
for( j = 0; j < 3; j++ ) {
for( i = 0; i < 3; i++ )
printf( "%3d ", p[j * lsk + i * psk + 1] );
printf("\n");
}
printf( "G = %d\n", G );
printf( "theta = %d\n", theta );
printf( "low_theta = %d\n", low_theta );
printf( "high_theta = %d\n", high_theta );
printf( "residual = %d\n", residual );
printf( "lowa = %d\n", lowa );
printf( "lowb = %d\n", lowb );
printf( "low = %d\n", low );
printf( "higha = %d\n", higha );
printf( "highb = %d\n", highb );
printf( "high = %d\n", high );
if( G <= low || G < high )
printf( "thin\n" );
printf( "\n" );
}
#endif /*DEBUG*/
/* Set G to 0 if it's not the local maxima in
* the direction of the gradient.
*/
if( G <= low ||
G < high )
G = 0;
q[band] = G;
p += 2;
}
q += out_bands;
}
}
return( 0 );
}
/* Remove non-maximal edges. At each point, compare the G to the G in either
* direction and 0 it if it's not the largest.
*/
static int
vips_canny_nonmaxi( VipsImage *in, VipsImage **out )
{
*out = vips_image_new();
if( vips_image_pipelinev( *out,
VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
return( -1 );
(*out)->Bands /= 2;
(*out)->Xsize -= 2;
(*out)->Ysize -= 2;
if( vips_image_generate( *out,
vips_start_one, vips_canny_nonmaxi_generate, vips_stop_one,
in, NULL ) )
return( -1 );
return( 0 );
}
static int
vips_canny_thresh_generate( VipsRegion *or,
void *vseq, void *a, void *b, gboolean *stop )
{
VipsRegion *in = (VipsRegion *) vseq;
VipsCanny *canny = (VipsCanny *) b;
VipsRect *r = &or->valid;
int sz = r->width * in->im->Bands;
VipsPel low = canny->low;
VipsPel high = canny->high;
int x, y;
if( vips_region_prepare( in, r ) )
return( -1 );
for( y = 0; y < r->height; y++ ) {
VipsPel *p = (VipsPel * restrict)
VIPS_REGION_ADDR( in, r->left, r->top + y );
VipsPel *q = (VipsPel * restrict)
VIPS_REGION_ADDR( or, r->left, r->top + y );
for( x = 0; x < sz; x++ ) {
int v;
v = p[x];
if( v <= low )
v = 0;
else if( v <= high )
v = 128;
else
v = 255;
q[x] = v;
}
}
return( 0 );
}
static int
vips_canny_thresh( VipsCanny *canny, VipsImage *in, VipsImage **out )
{
*out = vips_image_new();
if( vips_image_pipelinev( *out,
VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
return( -1 );
if( vips_image_generate( *out,
vips_start_one, vips_canny_thresh_generate, vips_stop_one,
in, canny ) )
return( -1 );
return( 0 );
}
static int
vips_canny_build( VipsObject *object )
{
VipsCanny *canny = (VipsCanny *) object;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 20 );
VipsImage *in;
VipsImage *Gx;
VipsImage *Gy;
if( VIPS_OBJECT_CLASS( vips_canny_parent_class )->build( object ) )
return( -1 );
in = canny->in;
if( vips_gaussblur( in, &t[0], canny->sigma, NULL ) )
return( -1 );
in = t[0];
if( vips_canny_gradient_simple( in, &Gx, &Gy ) )
return( -1 );
/* Form (G, theta), with theta coded.
*/
canny->args[0] = Gx;
canny->args[1] = Gy;
canny->args[2] = NULL;
if( vips_canny_polar( canny->args, &t[9] ) )
return( -1 );
in = t[9];
/* Expand by two pixels all around, then thin.
*/
if( vips_embed( in, &t[10], 1, 1, in->Xsize + 2, in->Ysize + 2,
"extend", VIPS_EXTEND_COPY,
NULL ) )
return( -1 );
if( canny->interpolate ) {
if( vips_canny_nonmaxi( t[10], &t[11] ) )
return( -1 );
}
else {
if( vips_canny_nonmax( t[10], &t[11] ) )
return( -1 );
}
in = t[11];
/* Double threshold.
*/
if( vips_canny_thresh( canny, in, &t[12] ) )
return( -1 );
in = t[12];
g_object_set( object, "out", vips_image_new(), NULL );
if( vips_image_write( in, canny->out ) )
return( -1 );
return( 0 );
}
static void
vips_canny_class_init( VipsCannyClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "canny";
object_class->description = _( "gaussian blur" );
object_class->build = vips_canny_build;
operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
VIPS_ARG_IMAGE( class, "in", 1,
_( "Input" ),
_( "Input image" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsCanny, in ) );
VIPS_ARG_IMAGE( class, "out", 2,
_( "Output" ),
_( "Output image" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsCanny, out ) );
VIPS_ARG_DOUBLE( class, "sigma", 10,
_( "Sigma" ),
_( "Sigma of Gaussian" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsCanny, sigma ),
0.01, 1000, 1.4 );
VIPS_ARG_DOUBLE( class, "low", 11,
_( "Low" ),
_( "Low threshold" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsCanny, low ),
-INFINITY, INFINITY, 3.0 );
VIPS_ARG_DOUBLE( class, "high", 12,
_( "High" ),
_( "High threshold" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsCanny, high ),
-INFINITY, INFINITY, 7.0 );
VIPS_ARG_BOOL( class, "interpolate", 13,
_( "Interpolate" ),
_( "Interpolate gradient angles" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsCanny, interpolate ),
FALSE );
}
static void
vips_canny_init( VipsCanny *canny )
{
canny->sigma = 1.4;
canny->low = 3.0;
canny->high = 7.0;
}
/**
* vips_canny: (method)
* @in: input image
* @out: (out): output image
* @sigma: how large a mask to use
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @sigma: %gdouble, sigma for gaussian blur
*
* See also: vips_gaussblur().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_canny( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "canny", ap, in, out );
va_end( ap );
return( result );
}