| /* histogram normalisation and cumulativisation |
| * |
| * Author: N. Dessipris |
| * Written on: 02/08/1990 |
| * 24/5/95 JC |
| * - tidied up and ANSIfied |
| * 20/7/95 JC |
| * - smartened up again |
| * - now works for hists >256 elements |
| * 3/3/01 JC |
| * - broken into cum and norm ... helps im_histspec() |
| * - better behaviour for >8 bit hists |
| * 31/10/05 JC |
| * - was broken for vertical histograms, gah |
| * - neater im_histnorm() |
| * 23/7/07 |
| * - eek, off by 1 for more than 1 band hists |
| * 12/5/08 |
| * - histcum works for signed hists now as well |
| * 24/3/10 |
| * - gtkdoc |
| * - small cleanups |
| */ |
| |
| /* |
| |
| 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 <vips/vips.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| #define ACCUMULATE( ITYPE, OTYPE ) { \ |
| for( b = 0; b < nb; b++ ) { \ |
| ITYPE *p = (ITYPE *) in->data; \ |
| OTYPE *q = (OTYPE *) outbuf; \ |
| OTYPE total; \ |
| \ |
| total = 0; \ |
| for( x = b; x < mx; x += nb ) { \ |
| total += p[x]; \ |
| q[x] = total; \ |
| } \ |
| } \ |
| } |
| |
| /** |
| * im_histcum: |
| * @in: input image |
| * @out: output image |
| * |
| * Form cumulative histogram. |
| * |
| * See also: im_histnorm(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_histcum( IMAGE *in, IMAGE *out ) |
| { |
| const int px = in->Xsize * in->Ysize; |
| const int nb = vips_bandfmt_iscomplex( in->BandFmt ) ? |
| in->Bands * 2 : in->Bands; |
| const int mx = px * nb; |
| |
| PEL *outbuf; |
| int b, x; |
| |
| if( im_check_uncoded( "im_histcum", in ) || |
| im_check_hist( "im_histcum", in ) || |
| im_iocheck( in, out ) ) |
| return( -1 ); |
| |
| if( im_cp_desc( out, in ) ) |
| return( -1 ); |
| out->Xsize = px; |
| out->Ysize = 1; |
| if( vips_bandfmt_isuint( in->BandFmt ) ) |
| out->BandFmt = IM_BANDFMT_UINT; |
| else if( vips_bandfmt_isint( in->BandFmt ) ) |
| out->BandFmt = IM_BANDFMT_INT; |
| if( im_setupout( out ) ) |
| return( -1 ); |
| |
| if( !(outbuf = im_malloc( out, IM_IMAGE_SIZEOF_LINE( out ))) ) |
| return( -1 ); |
| |
| switch( in->BandFmt ) { |
| case IM_BANDFMT_CHAR: |
| ACCUMULATE( signed char, signed int ); break; |
| case IM_BANDFMT_UCHAR: |
| ACCUMULATE( unsigned char, unsigned int ); break; |
| case IM_BANDFMT_SHORT: |
| ACCUMULATE( signed short, signed int ); break; |
| case IM_BANDFMT_USHORT: |
| ACCUMULATE( unsigned short, unsigned int ); break; |
| case IM_BANDFMT_INT: |
| ACCUMULATE( signed int, signed int ); break; |
| case IM_BANDFMT_UINT: |
| ACCUMULATE( unsigned int, unsigned int ); break; |
| |
| case IM_BANDFMT_FLOAT: |
| case IM_BANDFMT_COMPLEX: |
| ACCUMULATE( float, float ); break; |
| case IM_BANDFMT_DOUBLE: |
| case IM_BANDFMT_DPCOMPLEX: |
| ACCUMULATE( double, double ); break; |
| |
| default: |
| g_assert( 0 ); |
| } |
| |
| if( im_writeline( 0, out, outbuf ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| |
| /** |
| * im_histnorm: |
| * @in: input image |
| * @out: output image |
| * |
| * Normalise histogram ... normalise range to make it square (ie. max == |
| * number of elements). Normalise each band separately. |
| * |
| * See also: im_histcum(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_histnorm( IMAGE *in, IMAGE *out ) |
| { |
| const int px = in->Xsize * in->Ysize; |
| DOUBLEMASK *stats; |
| double *a, *b; |
| int i; |
| IMAGE *t1; |
| int fmt; |
| |
| /* Need max for each channel. |
| */ |
| if( !(a = IM_ARRAY( out, in->Bands, double )) || |
| !(b = IM_ARRAY( out, in->Bands, double )) || |
| !(stats = im_stats( in )) ) |
| return( -1 ); |
| |
| /* Scale each channel by px / channel max |
| */ |
| for( i = 0; i < in->Bands; i++ ) { |
| a[i] = px / stats->coeff[6 + 1 + 6*i]; |
| b[i] = 0; |
| } |
| |
| im_free_dmask( stats ); |
| |
| if( !(t1 = im_open_local( out, "im_histnorm:2", "p" )) || |
| im_lintra_vec( in->Bands, a, in, b, t1 ) ) |
| return( -1 ); |
| |
| /* Make output format as small as we can. |
| */ |
| if( px <= 256 ) |
| fmt = IM_BANDFMT_UCHAR; |
| else if( px <= 65536 ) |
| fmt = IM_BANDFMT_USHORT; |
| else |
| fmt = IM_BANDFMT_UINT; |
| |
| if( im_clip2fmt( t1, out, fmt ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| /** |
| * im_histeq: |
| * @in: input image |
| * @out: output image |
| * |
| * Histogram equalisation: normalised cumulative histogram. |
| * |
| * See also: im_heq(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_histeq( IMAGE *in, IMAGE *out ) |
| { |
| IMAGE *t1; |
| |
| /* Normalised cumulative. |
| */ |
| if( !(t1 = im_open_local( out, "im_histeq", "p" )) || |
| im_histcum( in, t1 ) || |
| im_histnorm( t1, out ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |