Other Alias

im_avg, im_deviate, im_minpos, im_max, im_maxpos## 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 computations 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.## COPYRIGHT

N. Dessipris

## AUTHOR

N. Dessipris - 24/04/1991J. Cupitt - 21/7/93