mlib_imagestddev(3mlib) sunos man page | unix.com

mlib_ImageStdDev(3MLIB) 				    mediaLib Library Functions					   mlib_ImageStdDev(3MLIB)

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 stan-
		       dard 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 TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

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

SunOS 5.10							    10 Nov 2004 					   mlib_ImageStdDev(3MLIB)