Content-type: text/html Man page of mlib_ImageStdDev

mlib_ImageStdDev

Section: mediaLib Library Functions (3MLIB)
Updated: 2 Mar 2007
Index Return to Main Contents
 

NAME

mlib_ImageStdDev - image standard deviation  

SYNOPSIS

cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>

mlib_status mlib_ImageStdDev(mlib_d64 *sdev, const mlib_image *img,
    const mlib_d64 *mean);

 

DESCRIPTION

The mlib_ImageStdDev() function computes the standard deviation for each channel in the source image.

It uses the following equation:

              1     w-1 h-1
sdev[i] = { ----- * SUM SUM (img[x][y][i] - mean[i])**2 }**0.5
            w*h    x=0 y=0

where, in the case of mean == NULL,

            1     w-1 h-1
mean[i] = ----- * SUM SUM img[x][y][i]
          w*h    x=0 y=0

 

PARAMETERS

The function takes the following arguments:

sdev

Pointer to standard deviation array, whose size is the number of channels in the source image. sdev[i] contains the standard deviation of channel i.

img

Pointer to input image.

mean

Pointer to pre-computed mean array for each channel. (If NULL, it will be computed.) mean[i] contains the mean of channel i.

 

RETURN VALUES

The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.  

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE

Interface StabilityCommitted

MT-Level

 

SEE ALSO

mlib_ImageMean(3MLIB), mlib_ImageMean_Fp(3MLIB), mlib_ImageStdDev_Fp(3MLIB), attributes(5)


 

Index

NAME
SYNOPSIS
DESCRIPTION
PARAMETERS
RETURN VALUES
ATTRIBUTES
SEE ALSO

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Time: 02:38:18 GMT, October 02, 2010