| /* im_compass |
| * |
| * Author: N. Dessipris (Copyright, N. Dessipris 1991) |
| * Written on: 08/05/1991 |
| * Modified on: |
| * 11/3/01 JC |
| * - rewritten, calling im_conv() and im_maxvalue() |
| * 3/2/10 |
| * - gtkdoc |
| */ |
| |
| /* |
| |
| 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 <limits.h> |
| #include <assert.h> |
| |
| #include <vips/vips.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| /** |
| * im_compass: |
| * @in: input image |
| * @out: output image |
| * @mask: convolution mask |
| * |
| * @in is convolved 8 times with @mask, each time @mask is rotated by 45 |
| * degrees. Each output pixel is the largest absolute value of the 8 |
| * convolutions. |
| * |
| * See also: im_lindetect(), im_gradient(), im_conv(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_compass( IMAGE *in, IMAGE *out, INTMASK *mask ) |
| { |
| IMAGE *filtered[8]; |
| IMAGE *absed[8]; |
| int i; |
| |
| if( im_open_local_array( out, filtered, 8, "im_compass:1", "p" ) || |
| im_open_local_array( out, absed, 8, "im_compass:2", "p" ) ) |
| return( -1 ); |
| |
| for( i = 0; i < 8; i++ ) { |
| if( im_conv( in, filtered[i], mask ) || |
| !(mask = im_local_imask( out, |
| im_rotate_imask45( mask, mask->filename ) )) ) |
| return( -1 ); |
| } |
| |
| for( i = 0; i < 8; i++ ) |
| if( im_abs( filtered[i], absed[i] ) ) |
| return( -1 ); |
| |
| return( im_maxvalue( absed, out, 8 ) ); |
| } |
| |
| /** |
| * im_lindetect: |
| * @in: input image |
| * @out: output image |
| * @mask: convolution mask |
| * |
| * @in is convolved four times with @mask, each time @mask is rotated by 45 |
| * degrees. Each output pixel is the largest absolute value of the four |
| * convolutions. |
| * |
| * See also: im_compass(), im_gradient(), im_conv(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_lindetect( IMAGE *in, IMAGE *out, INTMASK *mask ) |
| { |
| IMAGE *filtered[4]; |
| IMAGE *absed[4]; |
| int i; |
| |
| if( im_open_local_array( out, filtered, 4, "im_lindetect:1", "p" ) || |
| im_open_local_array( out, absed, 4, "im_lindetect:2", "p" ) ) |
| return( -1 ); |
| |
| for( i = 0; i < 4; i++ ) { |
| if( im_conv( in, filtered[i], mask ) || |
| !(mask = im_local_imask( out, |
| im_rotate_imask45( mask, mask->filename ) )) ) |
| return( -1 ); |
| } |
| |
| for( i = 0; i < 4; i++ ) |
| if( im_abs( filtered[i], absed[i] ) ) |
| return( -1 ); |
| |
| return( im_maxvalue( absed, out, 4 ) ); |
| } |
| |
| /** |
| * im_gradient: |
| * @in: input image |
| * @out: output image |
| * @mask: convolution mask |
| * |
| * @in is convolved with @mask and with @mask after a 90 degree rotation. The |
| * result is the sum of the absolute value of the two convolutions. |
| * |
| * See also: im_lindetect(), im_gradient(), im_conv(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_gradient( IMAGE *in, IMAGE *out, INTMASK *mask ) |
| { |
| IMAGE *t[4]; |
| INTMASK *rmask; |
| |
| if( im_open_local_array( out, t, 4, "im_gradient", "p" ) ) |
| return( -1 ); |
| |
| if( !(rmask = im_local_imask( out, |
| im_rotate_imask90( mask, mask->filename ) )) ) |
| return( -1 ); |
| |
| if( im_conv( in, t[0], mask ) || |
| im_conv( in, t[1], rmask ) || |
| im_abs( t[0], t[2] ) || |
| im_abs( t[1], t[3] ) || |
| im_add( t[2], t[3], out ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |