| .TH STATS 3 "24 April 1991" |
| .SH NAME |
| im_avg, im_deviate, im_min, im_minpos, im_max, im_maxpos \- find the mean, standard deviation, minimum and maximum of an image |
| .SH SYNOPSIS |
| .B #include <vips/vips.h> |
| |
| .B int im_avg(im, out) |
| .br |
| .B IMAGE *im; |
| .br |
| .B double *out; |
| |
| .B int im_deviate(im, out) |
| .br |
| .B IMAGE *im; |
| .br |
| .B double *out; |
| |
| .B int im_min(im, out) |
| .br |
| .B IMAGE *im; |
| .br |
| .B double *out; |
| |
| .B int im_minpos(im, xpos, ypos, min) |
| .br |
| .B IMAGE *im; |
| .br |
| .B int *xpos, *ypos; |
| .br |
| .B double *min; |
| |
| .B int im_max(im, out) |
| .br |
| .B IMAGE *im; |
| .br |
| .B double *out; |
| |
| .B int im_maxpos(im, xpos, ypos, max) |
| .br |
| .B IMAGE *im; |
| .br |
| .B int *xpos, *ypos; |
| .br |
| .B double *max; |
| |
| .SH DESCRIPTION |
| These functions find the mean, standard deviation, minimum, maximum of an image. |
| They operate on all bands of the input image. Use |
| .B 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}). |
| |
| .B 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. |
| |
| .B 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. |
| |
| .B 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. |
| |
| .B 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. |
| |
| .B 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. |
| |
| .B 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. |
| .SH RETURN VALUE |
| All functions return 0 on success and -1 on error. |
| .SH SEE ALSO |
| im_exptra(3), im_lintra(3), im_abs(3), im_stats(3). |
| .SH COPYRIGHT |
| .br |
| N. Dessipris |
| .SH AUTHOR |
| N. Dessipris \- 24/04/1991 |
| .br |
| J. Cupitt \- 21/7/93 |