124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/* @(#) Function to perform black level correction given black image
|
|
* @(#) designed for PAD camera single field black to apply in blocks
|
|
* @(#) as each is reused for higher resolution pels (eg: 6 8 for Progres)
|
|
* @(#) IM_BANDFMT_UCHAR images only. Always writes UCHAR.
|
|
* @(#) int im_clamp(in, w, out, hstep, vstep)
|
|
* @(#) IMAGE *in, *w, *out; int hstep, vstep;
|
|
* @(#) - Compute clip(image - (black)) ie subtract black no negatives
|
|
* @(#) scales for low res Progres images to replicate black value
|
|
* @(#) Returns 0 on success and -1 on error
|
|
* fiddle at your peril - nasty code
|
|
* Copyright: 1993 KM
|
|
* 20/8/93
|
|
*/
|
|
|
|
/*
|
|
|
|
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
|
|
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include <config.h>
|
|
#endif /*HAVE_CONFIG_H*/
|
|
#include <glib/gi18n-lib.h>
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include <vips/vips.h>
|
|
#include <vips/vips7compat.h>
|
|
#include <vips/internal.h>
|
|
|
|
int
|
|
im_clamp( IMAGE *in, IMAGE *out, IMAGE *black, int hstep, int vstep )
|
|
{ PEL *p, *blk, *bline, *bexp;
|
|
PEL *q, *outbuf;
|
|
int rep;
|
|
int x, y, bnd;
|
|
int temp, blacky, newblacky;
|
|
|
|
if( im_iocheck( in, out ) )
|
|
return( -1 );
|
|
if( in->Bbits != 8 ||
|
|
in->Coding != IM_CODING_NONE || in->BandFmt != IM_BANDFMT_UCHAR ) {
|
|
im_error( "im_clamp", "%s", _( "bad input format" ) );
|
|
return( -1 );
|
|
}
|
|
if( black->Bbits != 8 ||
|
|
black->Coding != IM_CODING_NONE || black->BandFmt != IM_BANDFMT_UCHAR ) {
|
|
im_error( "im_clamp", "%s", _( "bad black format" ) );
|
|
return( -1 );
|
|
}
|
|
|
|
/* Set up the output header.
|
|
*/
|
|
if( im_cp_desc( out, in ) )
|
|
return( -1 );
|
|
if( im_setupout( out ) )
|
|
return( -1 );
|
|
|
|
/* Make buffer for expanded black line
|
|
*/
|
|
if( !(bline = (PEL *) im_malloc( out, black->Bands * hstep * in->Xsize )) )
|
|
return( -1 );
|
|
/* Make buffer we write to.
|
|
*/
|
|
if( !(outbuf = (PEL *) im_malloc( out, out->Bands * out->Xsize )) )
|
|
return( -1 );
|
|
blacky = -1;
|
|
p = (PEL *) in->data;
|
|
|
|
for( y = 0; y < in->Ysize; y++ ) {
|
|
/* calc corresponding black line - get new one if different */
|
|
newblacky = (vstep * black->Ysize - in->Ysize + y)/vstep;
|
|
if( newblacky != blacky){
|
|
blacky = newblacky;
|
|
/* time to expand a new black line */
|
|
blk = (PEL *) (black->data +
|
|
black->Xsize * black->Bands * blacky);
|
|
for(bexp = bline, x = 0; x < black->Xsize; x++){
|
|
for(rep = 0; rep < hstep; rep++)
|
|
for(q=blk, bnd = 0; bnd < in->Bands; bnd++)
|
|
*bexp++ = *q++;
|
|
blk += black->Bands;
|
|
}
|
|
}
|
|
|
|
/* correct a line of image */
|
|
bexp = bline;
|
|
q = outbuf;
|
|
for( x = 0; x < (out->Bands * out->Xsize); x++ ) {
|
|
temp = ((int) *p++ - *bexp++);
|
|
if( temp < 0 ) temp = 0;
|
|
*q++ = (PEL)temp;
|
|
}
|
|
|
|
if( im_writeline( y, out, outbuf ) )
|
|
return( -1 );
|
|
} /* end of a line */
|
|
|
|
return( 0 );
|
|
}
|