STATS(3) STATS(3)
NAME
im_avg, im_deviate, im_min, im_minpos, im_max, im_maxpos - find the
mean, standard deviation, minimum and maximum of an image
SYNOPSIS
#include <vips/vips.h>
int im_avg(im, out)
IMAGE *im;
double *out;
int im_deviate(im, out)
IMAGE *im;
double *out;
int im_min(im, out)
IMAGE *im;
double *out;
int im_minpos(im, xpos, ypos, min)
IMAGE *im;
int *xpos, *ypos;
double *min;
int im_max(im, out)
IMAGE *im;
double *out;
int im_maxpos(im, xpos, ypos, max)
IMAGE *im;
int *xpos, *ypos;
double *max;
DESCRIPTION
These functions find the mean, standard deviation, minimum, maximum of
an image. They operate on all bands of the input image. Use
im_stats(3) if you need to calculate on bands separately. All computa-
tions are carried out in double precision arithmetic. The standard
deviation is calculated using the formula:
Var{E} = 1 / (N - 1) * (E{X^2} - E{X}^2 / N)
stdev{E} = sqrt(Var{E}).
im_avg(3) finds the average of an image pointed by im. Takes as input
any non-complex image format and returns a double at the location
pointed by out.
im_deviate(3) finds the standard deviation of an image pointed by im.
Takes as input any non-complex image format and returns a double at the
location pointed by out.
im_min(3) finds the the minimum value of the image pointed by im and
returns it at the location pointed by out. Takes as input any image
format and returns a double at the location pointed by out. If input
is complex the min square amplitude (re*re+im*im) is returned.
im_minpos(3) finds the the minimum value of the image pointed by im and
returns it at the location pointed by out. The coordinates of the last
occurrence of min is returned at locations pointed by xpos, ypos. If
input is complex the min square amplitude (re*re+im*im) is returned.
im_max(3) finds the the maximum value of the image pointed by im and
returns it at the location pointed by out. If input is complex the max
square amplitude (re*re+im*im) is returned.
im_maxpos(3) finds the the maximum value of the image pointed by im and
returns it at the location pointed by max. The coordinates of the last
occurrence of max is returned at locations pointed by xpos, ypos. If
input is complex the max square amplitude (re*re+im*im) and its last
occurrence is returned.
RETURN VALUE
All functions return 0 on success and -1 on error.
SEE ALSO
im_exptra(3), im_lintra(3), im_abs(3), im_stats(3).
COPYRIGHT
N. Dessipris
AUTHOR
N. Dessipris - 24/04/1991
J. Cupitt - 21/7/93
24 April 1991 STATS(3)
im_avg 7.14.5 - Generated Fri Sep 5 20:40:34 CDT 2008