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