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im_avg, im_deviate, im_min, im_minpos, im_max, im_maxpos - find the mean, standard deviation, minimum and maximum of an image

#include<vips/vips.h>intim_avg(im,out)IMAGE*im;double*out;intim_deviate(im,out)IMAGE*im;double*out;intim_min(im,out)IMAGE*im;double*out;intim_minpos(im,xpos,ypos,min)IMAGE*im;int*xpos,*ypos;double*min;intim_max(im,out)IMAGE*im;double*out;intim_maxpos(im,xpos,ypos,max)IMAGE*im;int*xpos,*ypos;double*max;

These functions find the mean, standard deviation, minimum, maximum of an image. They operate on all bands of the input image. Useim_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.

All functions return 0 on success and -1 on error.

im_exptra(3), im_lintra(3), im_abs(3), im_stats(3).

N. Dessipris

N. Dessipris - 24/04/1991 J. Cupitt - 21/7/93 24 April 1991 STATS(3)