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mlib_imagestddev_fp(3mlib) [opensolaris man page]

mlib_ImageStdDev_Fp(3MLIB)				    mediaLib Library Functions					mlib_ImageStdDev_Fp(3MLIB)

NAME
mlib_ImageStdDev_Fp - image standard deviation SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ] #include <mlib.h> mlib_status mlib_ImageStdDev_Fp(mlib_d64 *sdev, const mlib_image *img, const mlib_d64 *mean); DESCRIPTION
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 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 devia- tion 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 |Committed | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
mlib_ImageMean(3MLIB), mlib_ImageMean_Fp(3MLIB), mlib_ImageStdDev(3MLIB), attributes(5) SunOS 5.11 2 Mar 2007 mlib_ImageStdDev_Fp(3MLIB)

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mlib_ImageNormCrossCorrel_Fp(3MLIB)									       mlib_ImageNormCrossCorrel_Fp(3MLIB)

NAME
mlib_ImageNormCrossCorrel_Fp - normalized cross correlation SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ] #include <mlib.h> mlib_status mlib_ImageNormCrossCorrel_Fp(mlib_d64 *correl, const mlib_image *img1, const mlib_image *img2, const mlib_d64 *mean2, const mlib_d64 *sdev2); The mlib_ImageNormCrossCorrel_Fp() function computes the normalized cross-correlation coefficients between a pair of floating-point images, on a per-channel basis. It uses the following equations: w-1 h-1 SUM SUM (d1[x][y][i] * d2[x][y][i]) x=0 y=0 correl[i] = ------------------------------------- s1[i] * s2[i] d1[x][y][i] = img1[x][y][i] - m1[i] d2[x][y][i] = img2[x][y][i] - m2[i] 1 w-1 h-1 m1[i] = ----- * SUM SUM img1[x][y][i] w*h x=0 y=0 1 w-1 h-1 m2[i] = ----- * SUM SUM img2[x][y][i] w*h x=0 y=0 w-1 h-1 s1[i] = sqrt{ SUM SUM (img1[x][y][i] - m1[i])**2 } x=0 y=0 w-1 h-1 s2[i] = sqrt{ SUM SUM (img2[x][y][i] - m2[i])**2 } x=0 y=0 where w and h are the width and height of the images, respectively; m1 and m2 are the mean arrays of the first and second images, respec- tively; s1 and s2 are the un-normalized standard deviation arrays of the first and second images, respectively. In usual cases, the normalized cross-correlation coefficient is in the range of [-1.0, 1.0]. In the case of (s1[i] == 0) or (s2[i] == 0), where a constant image channel is involved, the normalized cross-correlation coefficient is defined as follows: #define signof(x) ((x > 0) ? 1 : ((x < 0) ? -1 : 0)) if ((s1[i] == 0.) || (s2[i] == 0.)) { if ((s1[i] == 0.) && (s2[i] == 0.)) { if (signof(m1[i]) == signof(m2[i]) { correl[i] = 1.0; } else { correl[i] = -1.0; } } else { correl[i] = -1.0; } } The two images must have the same type, the same size, and the same number of channels. They can have 1, 2, 3 or 4 channels. They can be of type MLIB_FLOAT or MLIB_DOUBLE. If (mean2 == NULL) or (sdev2 == NULL), then m2 and s2 are calculated in this function according to the formulas shown above. Otherwise, they are calculated as follows: m2[i] = mean2[i]; s2[i] = sdev2[i] * sqrt(w*h); where mean2 and sdev2 can be the output of mlib_ImageMean() and mlib_ImageStdDev(), respectively. In some cases, the resulting coefficients of this function could be NaN, Inf, or -Inf. The function takes the following arguments: correl Pointer to normalized cross correlation array on a channel basis. The array must be the size of channels in the images. correl[i] contains the cross-correlation of channel i. img1 Pointer to first image. img2 Pointer to second image. mean2 Pointer to the mean array of the second image. sdev2 Pointer to the standard deviation array of the second image. The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE. See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Evolving | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ mlib_ImageAutoCorrel(3MLIB), mlib_ImageAutoCorrel_Fp(3MLIB), mlib_ImageCrossCorrel(3MLIB), mlib_ImageCrossCorrel_Fp(3MLIB), mlib_ImageNorm- CrossCorrel(3MLIB), attributes(5) 23 May 2005 mlib_ImageNormCrossCorrel_Fp(3MLIB)

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