started sharpen.c
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John Cupitt
parent
941982786f
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585
libvips/convolution/sharpen.c
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585
libvips/convolution/sharpen.c
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@ -0,0 +1,585 @@
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/* Cored sharpen of LABQ image.
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*
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* Usage:
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*
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* int im_sharpen( IMAGE *in, IMAGE *out,
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* int mask_size,
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* int x1, int x2,
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* double m1, double m2 )
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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: 1995 A. Abbood
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* Author: A. Abbood
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* Written on: 30/01/1995
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* 15/5/95 JC
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* - updated for latest 7.3 mods
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* - m3 parameter removed
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* - bug fixes and speed-ups
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* 4/7/95 JC
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* - x3 parameter added
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* - xs are now double
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* 6/7/95 JC
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* - xs are now ys
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* - better LUT generation
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* 12/3/01 JC
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* - uses seperable convolution for umask
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* - tiny clean ups
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* 23/7/01 JC
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* - fix for band extract index changed
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* 21/4/04
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* - switched to gaussian mask and radius
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* 20/11/04
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* - uses extract_bands() to remove and reattach ab for slight speedup
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* - accepts LabS as well as LabQ for slight speedup
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* - small code tidies
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* - ~15% speed up in total
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* 29/11/06
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* - convolve first to help region sharing
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* 3/2/10
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* - gtkdoc
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* - cleanups
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* 13/11/13
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* - redo as a class
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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., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 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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/*
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#define DEBUG
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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 <math.h>
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#include <vips/vips.h>
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typedef struct _VipsSharpen {
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VipsOperation parent_instance;
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VipsImage *in;
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VipsImage *out;
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int mask_size,
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double x1;
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double y2;
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double y3;
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double m1;
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double m2;
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double x2;
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double x3;
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/* Parameters scaled up to int.
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*
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* We need indexes in the range [-x3,x2], so add x3 to
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* indexes before starting to index table.
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*/
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int ix1;
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int ix2;
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int ix3;
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/* The lut we build.
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*/
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int *lut;
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} VipsSharpen;
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typedef VipsOperationClass VipsSharpenClass;
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G_DEFINE_TYPE( VipsSharpen, vips_sharpen, VIPS_TYPE_OPERATION );
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/* Take the difference of in1 and in2 and LUT it.
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*/
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static void
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buf_difflut( short **in, short *out, int n, SharpenLut *slut )
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{
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int range = slut->x2 + slut->x3;
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int *lut = slut->lut;
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int x3 = slut->x3;
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short *p1 = in[1];
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short *p2 = in[0];
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int i;
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for( i = 0; i < n; i++ ) {
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int v1 = p1[i];
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int v2 = p2[i];
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/* v2 is the area average. If this is zero, then we pass the
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* original image through unaltered.
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*/
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if( v2 == 0 )
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out[i] = v1;
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else {
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/* Find difference. Offset by x3 to get the expected
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* range of values.
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*/
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int s1 = x3 + (v1 - v2);
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int s2;
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/* Clip to LUT range.
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*/
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if( s1 < 0 )
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s1 = 0;
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else if( s1 > range )
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s1 = range;
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/* Transform!
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*/
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s2 = v1 + lut[s1];
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/* Clip to LabS range.
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*/
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if( s2 < 0 )
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s2 = 0;
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else if( s2 > 32767 )
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s2 = 32767;
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/* And write.
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*/
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out[i] = s2;
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}
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}
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}
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int
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im_sharpen( IMAGE *in, IMAGE *out,
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int mask_size,
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double x1, double y2, double y3,
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double m1, double m2 )
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{
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IMAGE *arry[3];
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IMAGE *t[4];
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VipsImage *mask;
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/* Turn y parameters into xs.
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*/
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double x2 = (y2 - x1 * (m1 - m2)) / m2;
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double x3 = (y3 - x1 * (m1 - m2)) / m2;
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if( in->Coding == IM_CODING_LABQ ) {
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IMAGE *tc[2];
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if( im_open_local_array( out, tc, 2, "im_sharpen:1", "p" ) ||
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im_LabQ2LabS( in, tc[0] ) ||
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im_sharpen( tc[0], tc[1],
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mask_size, x1, y2, y3, m1, m2 ) ||
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im_LabS2LabQ( tc[1], out ) )
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return( -1 );
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return( 0 );
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}
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/* Check IMAGE parameters
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*/
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if( im_piocheck( in, out ) ||
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im_check_uncoded( "im_sharpen", in ) ||
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im_check_bands( "im_gradcor", in, 3 ) ||
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im_check_format( "im_gradcor", in, IM_BANDFMT_SHORT ) )
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return( -1 );
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/* Check number range.
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*/
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if( x1 < 0 || x1 > 99 ||
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x2 < 0 || x2 > 99 ||
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x1 > x2 ||
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x3 < 0 || x3 > 99 ||
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x1 > x3 ) {
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im_error( "im_sharpen", "%s", _( "parameters out of range" ) );
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return( -1 );
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}
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/* Open a set of local image descriptors.
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*/
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if( im_open_local_array( out, t, 4, "im_sharpen:2", "p" ) )
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return( -1 );
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return( 0 );
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}
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/* Our sequence value: the region this sequence is using, and local stats.
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*/
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typedef struct {
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VipsRegion *ir; /* Input region */
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/* A 256-element hist for evry band.
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*/
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unsigned int **hist;
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} VipsSharpenSequence;
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static int
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vips_sharpen_stop( void *vseq, void *a, void *b )
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{
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VipsSharpenSequence *seq = (VipsSharpenSequence *) vseq;
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VipsImage *in = (VipsImage *) a;
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VIPS_UNREF( seq->ir );
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if( seq->hist ) {
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int i;
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for( i = 0; i < in->Bands; i++ )
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VIPS_FREE( seq->hist[i] );
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VIPS_FREE( seq->hist );
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}
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VIPS_FREE( seq );
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return( 0 );
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}
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static void *
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vips_sharpen_start( VipsImage *out, void *a, void *b )
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{
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VipsImage *in = (VipsImage *) a;
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VipsSharpenSequence *seq;
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int i;
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if( !(seq = VIPS_NEW( NULL, VipsSharpenSequence )) )
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return( NULL );
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seq->ir = NULL;
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seq->hist = NULL;
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if( !(seq->ir = vips_region_new( in )) ||
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!(seq->hist = VIPS_ARRAY( NULL, in->Bands, unsigned int * )) ) {
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vips_sharpen_stop( seq, NULL, NULL );
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return( NULL );
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}
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for( i = 0; i < in->Bands; i++ )
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if( !(seq->hist[i] = VIPS_ARRAY( NULL, 256, unsigned int )) ) {
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vips_sharpen_stop( seq, NULL, NULL );
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return( NULL );
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}
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return( seq );
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}
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static int
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vips_sharpen_generate( VipsRegion *or,
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void *vseq, void *a, void *b, gboolean *stop )
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{
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VipsRegion **in = (VipsRegion **) vseq;
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VipsSharpen *sharpen = (VipsSharpen *) b;
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VipsRect *r = &or->valid;
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VipsRect irect;
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if( vips_region_prepare( in[0], r ) ||
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vips_region_prepare( in[1], r ) )
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return( -1 );
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lsk = VIPS_REGION_LSKIP( seq->ir );
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centre = lsk * (local->height / 2) + bands * local->width / 2;
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for( y = 0; y < r->height; y++ ) {
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/* Get input and output pointers for this line.
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*/
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VipsPel *p = VIPS_REGION_ADDR( seq->ir, r->left, r->top + y );
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VipsPel *q = VIPS_REGION_ADDR( or, r->left, r->top + y );
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}
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}
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}
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return( 0 );
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}
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static int
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vips_sharpen_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsSharpen *local = (VipsSharpen *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 3 );
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VipsImage **args = (VipsImage **) vips_object_local_array( object, 2 );
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VipsImage *in;
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if( VIPS_OBJECT_CLASS( vips_sharpen_parent_class )->build( object ) )
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return( -1 );
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/* Turn y parameters into xs.
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*/
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sharpen->x2 = (sharpen->y2 -
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sharpen->x1 * (sharpen->m1 - sharpen->m2)) / sharpen->m2;
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sharpen->x3 = (sharpen->y3 -
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sharpen->x1 * (sharpen->m1 - sharpen->m2)) / sharpen->m2;
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in = sharpen->in;
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if( vips_colourspace( in, &t[0], VIPS_INTERPRETATION_LABS, NULL ) )
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return( -1 );
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in = t[0];
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if( vips_check_uncoded( class->nickname, in ) ||
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vips_check_bands( class->nickname, in, 3 ) ||
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vips_check_format( class->nickname, in, VIPS_FORMAT_SHORT ) )
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return( -1 );
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if( sharpen->x1 < 0 || sharpen->x1 > 99 ||
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sharpen->x2 < 0 || sharpen->x2 > 99 ||
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sharpen->x1 > sharpen->x2 ||
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sharpen->x3 < 0 || sharpen->x3 > 99 ||
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sharpen->x1 > sharpen->x3 ) {
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vips_error( class->nickname,
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"%s", _( "parameters out of range" ) );
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return( -1 );
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}
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/* Stop at 20% of max ... bit mean, but means mask radius is roughly
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* right.
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*/
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if( vips_gaussmat( &t[1], radius / 2, 0.2,
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"separable", TRUE,
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"integer", TRUE,
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NULL ) )
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return( -1 );
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/* Build the int lut.
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*/
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sharpen->ix1 = x1 * 327.67;
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sharpen->ix2 = x2 * 327.67;
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sharpen->ix3 = x3 * 327.67;
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if( !(sharpen->lut = VIPS_ARRAY( sharpen->out,
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sharpen->ix2 + sharpen->ix3 + 1, int )) )
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return( -1 );
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for( i = 0; i < sharpen->ix1; i++ ) {
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slut->lut[sharpen->ix3 + i] = i * m1;
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slut->lut[sharpen->ix3 - i] = -i * m1;
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}
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for( i = sharpen->ix1; i <= sharpen->ix2; i++ )
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slut->lut[sharpen->ix3 + i] =
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sharpen->ix1 * sharpen->m1 +
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(i - sharpen->ix1) * sharpen->m2;
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for( i = sharpen->ix1; i <= sharpen->ix3; i++ )
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slut->lut[sharpen->ix3 - i] =
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-(sharpen->ix1 * sharpen->m1 +
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(i - sharpen->ix1) * sharpen->m2);
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/* Extract L and ab, convolve L.
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*/
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if( vips_extract_band( in, &args[0], 0, NULL ) ||
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vips_extract_bands( in, &t[3], 1, "n", 2, NULL ) ||
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vips_convsep( args[0], &args[1], t[1], NULL ) )
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return( -1 );
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/* Set demand hints. FATSTRIP is good for us, as THINSTRIP will cause
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* too many recalculations on overlaps.
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*/
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t[5] = vips_image_new();
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if( vips_image_pipeline_array( t[5],
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VIPS_DEMAND_STYLE_FATSTRIP, args ) )
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return( -1 );
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if( vips_image_generate( t[5],
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vips_start_many, vips_sharpen_generate, vips_stop_many,
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args, sharpen ) )
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return( -1 );
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g_object_set( object, "out", vips_image_new(), NULL );
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/* Reattach ab.
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*/
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if( vips_bandjoin2( t[5], t[3], &t[6], NULL ) ||
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vips_image_write( t[6], sharpen->out ) )
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return( -1 );
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return( 0 );
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}
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static void
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vips_sharpen_class_init( VipsSharpenClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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object_class->nickname = "sharpen";
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object_class->description = _( "Unsharp masking for print" );
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object_class->build = vips_sharpen_build;
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VIPS_ARG_IMAGE( class, "in", 1,
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_( "Input" ),
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_( "Input image" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, in ) );
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VIPS_ARG_IMAGE( class, "out", 2,
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_( "Output" ),
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_( "Output image" ),
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VIPS_ARGUMENT_REQUIRED_OUTPUT,
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G_STRUCT_OFFSET( VipsSharpen, out ) );
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VIPS_ARG_INT( class, "mask_size", 4,
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_( "mask_size" ),
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_( "Mask radius" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, mask_radius ),
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1, 1000000, 7 );
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VIPS_ARG_DOUBLE( class, "x1", 4,
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_( "x1" ),
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_( "Flat/jaggy threshold" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, x1 ),
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1, 1000000, 1.5 );
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VIPS_ARG_DOUBLE( class, "y2", 5,
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_( "y2" ),
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_( "Maximum brightening" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, y2 ),
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1, 1000000, 20 );
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VIPS_ARG_DOUBLE( class, "y3", 6,
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_( "y3" ),
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_( "Maximum darkening" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, y3 ),
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1, 1000000, 50 );
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VIPS_ARG_DOUBLE( class, "m1", 6,
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_( "m1" ),
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_( "Slope for flat areas" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, m1 ),
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1, 1000000, 1 );
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VIPS_ARG_DOUBLE( class, "m2", 7,
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_( "m2" ),
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_( "Slope for jaggy areas" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, m2 ),
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1, 1000000, 2 );
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||||
}
|
||||
|
||||
static void
|
||||
vips_sharpen_init( VipsSharpen *sharpen )
|
||||
{
|
||||
sharpen->mask_size = 7;
|
||||
sharpen->x1 = 1.5;
|
||||
sharpen->y2 = 20;
|
||||
sharpen->y3 = 50;
|
||||
sharpen->m1 = 1;
|
||||
sharpen->m2 = 2;
|
||||
}
|
||||
|
||||
/**
|
||||
* vips_sharpen:
|
||||
* @in: input image
|
||||
* @out: output image
|
||||
* @mask_size: how large a mask to use
|
||||
* @x1: flat/jaggy threshold
|
||||
* @y2: maximum amount of brightening
|
||||
* @y3: maximum amount of darkening
|
||||
* @m1: slope for flat areas
|
||||
* @m2: slope for jaggy areas
|
||||
* @...: %NULL-terminated list of optional named arguments
|
||||
*
|
||||
* Selectively sharpen the L channel of a LAB image. Works for
|
||||
* #VIPS_CODING_LABQ and LABS images.
|
||||
*
|
||||
* The operation performs a gaussian blur of size @mask_size and subtracts
|
||||
* from @in to
|
||||
* generate a high-frequency signal. This signal is passed through a lookup
|
||||
* table formed from the five parameters and added back to @in.
|
||||
*
|
||||
* The lookup table is formed like this:
|
||||
*
|
||||
* |[
|
||||
^
|
||||
y2 |- - - - - -----------
|
||||
| /
|
||||
| / slope m2
|
||||
| .../
|
||||
-x1 | ... |
|
||||
-------------------...---------------------->
|
||||
| ... | x1
|
||||
|... slope m1
|
||||
/ |
|
||||
/ m2 |
|
||||
/ |
|
||||
/ |
|
||||
/ |
|
||||
/ |
|
||||
______/ _ _ _ _ _ _ | -y3
|
||||
|
|
||||
* ]|
|
||||
*
|
||||
* For printing, we recommend the following settings:
|
||||
*
|
||||
* |[
|
||||
mask_size == 7
|
||||
x1 == 1.5
|
||||
y2 == 20 (don't brighten by more than 20 L*)
|
||||
y3 == 50 (can darken by up to 50 L*)
|
||||
|
||||
m1 == 1 (some sharpening in flat areas)
|
||||
m2 == 2 (more sharpening in jaggy areas)
|
||||
* ]|
|
||||
*
|
||||
* If you want more or less sharpening, we suggest you just change the m1
|
||||
* and m2 parameters.
|
||||
*
|
||||
* The @mask_size parameter changes the width of the fringe and can be
|
||||
* adjusted according to the output printing resolution. As an approximate
|
||||
* guideline, use 3 for 4 pixels/mm (CRT display resolution), 5 for 8
|
||||
* pixels/mm, 7 for 12 pixels/mm and 9 for 16 pixels/mm (300 dpi == 12
|
||||
* pixels/mm). These figures refer to the image raster, not the half-tone
|
||||
* resolution.
|
||||
*
|
||||
* See also: im_conv().
|
||||
*
|
||||
* Returns: 0 on success, -1 on error.
|
||||
*/
|
||||
int
|
||||
vips_sharpen( VipsImage *in, VipsImage **out,
|
||||
int mask_size,
|
||||
double x1, double y2, double y3, double m1, double m2,
|
||||
... )
|
||||
{
|
||||
va_list ap;
|
||||
int result;
|
||||
|
||||
va_start( ap, m2 );
|
||||
result = vips_call_split( "sharpen", ap, in, out,
|
||||
mask_size, x1, y2, y3, m1, m2 );
|
||||
va_end( ap );
|
||||
|
||||
return( result );
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user