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hist hacking

This commit is contained in:
John Cupitt 2010-03-24 13:53:09 +00:00
parent 2c2aa11cd9
commit 7dfca6e806
4 changed files with 93 additions and 45 deletions
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53
libvips/histograms_lut/im_histeq.c
View File

@ -1,14 +1,4 @@
/* @(#) Takes as input a histogram and creates a lut which when applied
* @(#) on the original image, histogram equilises it.
* @(#)
* @(#) Histogram equalisation is carried out for each band of hist
* @(#) individually.
* @(#)
* @(#) int im_histeq( IMAGE *hist, IMAGE *lut )
* @(#)
* @(#) Returns 0 on sucess and -1 on error
*
* Copyright: 1991, N. Dessipris
/* histogram normalisation and cumulativisation
*
* Author: N. Dessipris
* Written on: 02/08/1990
@ -27,6 +17,9 @@
* - 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
*/
/*
@ -82,7 +75,16 @@
} \
}
/* Form cumulative histogram.
/**
* 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 )
@ -145,8 +147,18 @@ im_histcum( IMAGE *in, IMAGE *out )
return( 0 );
}
/* Normalise histogram ... normalise range to make it square (ie. max ==
/**
* 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 )
@ -193,7 +205,16 @@ im_histnorm( IMAGE *in, IMAGE *out )
return( 0 );
}
/* Histogram equalisation.
/**
* 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 )
@ -202,7 +223,9 @@ im_histeq( IMAGE *in, IMAGE *out )
/* Normalised cumulative.
*/
if( !t1 || im_histcum( in, t1 ) || im_histnorm( t1, out ) )
if( !(t1 = im_open_local( out, "im_histeq:1", "p" )) ||
im_histcum( in, t1 ) ||
im_histnorm( t1, out ) )
return( -1 );
return( 0 );

56
libvips/histograms_lut/im_histgr.c
View File

@ -1,16 +1,4 @@
/* @(#) im_histgr: make a histogram of an image and saves it into hist.
* @(#) If input is uchar, output is 256 by 1 image of uint. If input is
* @(#) ushort, output is max(image) + 1 by 1 image of uint. If bandno is
* @(#) zero, then output is has same number of bands as input, with each
* @(#) band being a separate histogram. Otherwise, bandno selects a band
* @(#) to find the histogram of.
* @(#)
* @(#) Usage:
* @(#) int im_histgr(image, hist, bandno)
* @(#) IMAGE *image, *hist;
* @(#) int bandno;
* @(#)
* @(#) Returns 0 on success and -1 on error
/* find histograms
*
* Copyright: 1990, 1991, N. Dessipris.
*
@ -29,6 +17,9 @@
* - tiny speed ups
* 21/1/07
* - number bands from zero
* 24/3/10
* - gtkdoc
* - small celanups
*/
/*
@ -292,6 +283,22 @@ find_ushort_hist_extract( REGION *reg, void *seq, void *a, void *b )
return( 0 );
}
/**
* im_histgr:
* @in: input image
* @out: output image
* @bandno: band to equalise
*
* Find the histogram of @in. Find the histogram for band @bandno (producing a
* one-band histogram), or for all bands (producing an n-band histogram) if
* @bandno is -1.
*
* @in must be u8 or u16. @out is always u32.
*
* See also: im_histgr(), im_histeq().
*
* Returns: 0 on success, -1 on error
*/
int
im_histgr( IMAGE *in, IMAGE *out, int bandno )
{
@ -304,30 +311,19 @@ im_histgr( IMAGE *in, IMAGE *out, int bandno )
/* Check images. PIO from in, WIO to out.
*/
if( im_pincheck( in ) || im_outcheck( out ) )
if( im_check_uncoded( "im_histgr", in ) ||
im_check_u8or16( "im_histgr", in ) ||
im_check_bandno( "im_histgr", in, bandno ) ||
im_pincheck( in ) ||
im_outcheck( out ) )
return( -1 );
if( in->Coding != IM_CODING_NONE ) {
im_error( "im_histgr", "%s", _( "uncoded images only" ) );
return( -1 );
}
/* Find the range of pixel values we must handle.
*/
if( in->BandFmt == IM_BANDFMT_UCHAR )
size = 256;
else if( in->BandFmt == IM_BANDFMT_USHORT )
size = 65536;
else {
im_error( "im_histgr", "%s", _( "input not uchar or ushort" ) );
return( -1 );
}
size = in->BandFmt == IM_BANDFMT_UCHAR ? 256 : 65536;
/* How many output bands?
*/
if( bandno > in->Bands || bandno < -1 ) {
im_error( "im_histgr", "%s", _( "bad band parameter" ) );
return( -1 );
}
if( bandno == -1 )
bands = in->Bands;
else

1
libvips/include/vips/check.h
View File

@ -54,6 +54,7 @@ int im_check_bands_1or3( const char *domain, IMAGE *in );
int im_check_bands( const char *domain, IMAGE *im, int bands );
int im_check_bands_1orn( const char *domain, IMAGE *im1, IMAGE *im2 );
int im_check_bands_same( const char *domain, IMAGE *im1, IMAGE *im2 );
int im_check_bandno( const char *domain, IMAGE *im, int bandno );
int im_check_int( const char *domain, IMAGE *im );
int im_check_uint( const char *domain, IMAGE *im );
int im_check_noncomplex( const char *domain, IMAGE *im );

28
libvips/iofuncs/check.c
View File

@ -971,6 +971,34 @@ im_check_bands_same( const char *domain, IMAGE *im1, IMAGE *im2 )
return( 0 );
}
/**
* im_check_bandno:
* @domain: the originating domain for the error message
* @im: image to check
* @bandno: band number
*
* @bandno should be a valid band number (ie. 0 to im->Bands - 1), or can be
* -1, meaning all bands.
* If not, set an error message
* and return non-zero.
*
* See also: im_error().
*
* Returns: 0 if OK, -1 otherwise.
*/
int
im_check_bandno( const char *domain, IMAGE *im, int bandno )
{
if( bandno < -1 ||
bandno > im->Bands - 1 ) {
im_error( domain, "bandno must be -1, or less than %d",
im->Bands );
return( -1 );
}
return( 0 );
}
/**
* im_check_format_same:
* @domain: the originating domain for the error message