cc [ flag... ] file... –lmlib [ library... ] #include <mlib.h> mlib_status mlib_ImageStdDev_Fp(mlib_d64 *sdev, const mlib_image *img, const mlib_d64 *mean);
The mlib_ImageStdDev_Fp() function computes the standard deviation for each channel in the floating-point 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
The function takes the following arguments:
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.
Pointer to input image.
Pointer to pre-computed mean array for each channel. (If NULL, it will be computed.) mean[i] contains the mean of channel i.
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
See attributes(5) for descriptions of the following attributes:
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mlib_ImageMean(3MLIB), mlib_ImageMean_Fp(3MLIB), mlib_ImageStdDev(3MLIB), attributes(5)