/**
* im_mpercent_hist:
* @hist: input histogram image
* @percent: threshold percentage
* @out: output threshold value
*
* Just like im_mpercent(), except it works on an image histogram. Handy if
* you want to run im_mpercent() several times without having to recompute the
* histogram each time.
*
* See also: im_mpercent().
*
* Returns: 0 on success, -1 on error
*/
int
im_mpercent_hist( IMAGE *hist, double percent, int *out )
{
IMAGE *base;
IMAGE *t[6];
double pos;
if( im_check_hist( "im_mpercent", hist ) )
return( -1 );
if( !(base = im_open( "im_mpercent", "p" )) )
return( -1 );
if( im_open_local_array( base, t, 6, "im_mpercent", "p" ) ) {
im_close( base );
return( -1 );
}
if( im_histcum( hist, t[1] ) ||
im_histnorm( t[1], t[2] ) ||
im_lessconst( t[2], t[3], percent * t[2]->Xsize ) ||
im_fliphor( t[3], t[4] ) ||
im_profile( t[4], t[5], 1 ) ||
im_avg( t[5], &pos ) ) {
im_close( base );
return( -1 );
}
im_close( base );
*out = pos;
return( 0 );
}
/* Find the number of non-zero pixels in a mask image.
*/
static int
count_nonzero( IMAGE *in, gint64 *count )
{
double avg;
if( im_avg( in, &avg ) )
return( -1 );
*count = (avg * in->Xsize * in->Ysize ) / 255.0;
return( 0 );
}
/**
* im_benchmark2:
* @in: input image
* @out: average image value
*
* This operation runs a single im_benchmarkn() and calculates the average
* pixel value. It's useful if you just want to test image input.
*
* See also: im_benchmarkn().
*
* Returns: 0 on success, -1 on error
*/
int
im_benchmark2( IMAGE *in, double *out )
{
IMAGE *t;
return(
!(t = im_open_local( in, "benchmarkn", "p" )) ||
im_benchmarkn( in, t, 1 ) ||
im_avg( t, out )
);
}
/* Get the value of pixel (0, 0). Use this to init the min/max value for
* im_max()/im_stats()/etc.
*/
int
im__value( IMAGE *im, double *value )
{
IMAGE *t;
if( !(t = im_open( "im__value", "p" )) )
return( -1 );
if( im_extract_areabands( im, t, 0, 0, 1, 1, 0, 1 ) ||
im_avg( t, value ) ) {
im_close( t );
return( -1 );
}
im_close( t );
return( 0 );
}
/* Measure into array.
*/
static int
measure_patches( IMAGE *im, double *coeff,
int left, int top, int width, int height,
int u, int v, int *sel, int nsel )
{
IMAGE *tmp;
int patch;
int i, j;
int m, n;
double avg, dev;
int x, y, w, h;
/* How large are the patches we are to measure?
*/
double pw = (double) width / (double) u;
double ph = (double) height / (double) v;
/* Set up sub to be the size we need for a patch.
*/
w = (pw + 1) / 2;
h = (ph + 1) / 2;
/* Loop through sel, picking out areas to measure.
*/
for( j = 0, patch = 0; patch < nsel; patch++ ) {
/* Sanity check. Is the patch number sensible?
*/
if( sel[patch] <= 0 || sel[patch] > u * v ) {
im_error( "im_measure",
_( "patch %d is out of range" ),
sel[patch] );
return( 1 );
}
/* Patch coordinates.
*/
m = (sel[patch] - 1) % u;
n = (sel[patch] - 1) / u;
/* Move sub to correct position.
*/
x = left + m * pw + (pw + 2) / 4;
y = top + n * ph + (ph + 2) / 4;
/* Loop through bands.
*/
for( i = 0; i < im->Bands; i++, j++ ) {
/* Make temp buffer to extract to.
*/
if( !(tmp = im_open( "patch", "t" )) )
return( -1 );
/* Extract and measure.
*/
if( im_extract_areabands( im, tmp, x, y, w, h, i, 1 ) ||
im_avg( tmp, &avg ) ||
im_deviate( tmp, &dev ) ) {
im_close( tmp );
return( -1 );
}
im_close( tmp );
/* Is the deviation large compared with the average?
* This could be a clue that our parameters have
* caused us to miss the patch. Look out for averages
* <0, or averages near zero (can get these if use
* im_measure() on IM_TYPE_LAB images).
*/
if( dev * 5 > fabs( avg ) && fabs( avg ) > 3 )
im_warn( "im_measure",
_( "patch %d, band %d: "
"avg = %g, sdev = %g" ),
patch, i, avg, dev );
/* Save results.
*/
coeff[j] = avg;
}
}
return( 0 );
}
