Mean

Computes the mean of image pixel values.

Syntax

Case 1: Operation on one-channel integer data

IppStatus ippiMean_<mod>(const Ipp<datatype>* pSrc, int srcStep, IppiSize roiSize, Ipp64f* pMean);

Supported values for mod:

8u_C1R

16u_C1R

16s_C1R

Case 2: Operation on one-channel floating-point data

IppStatus ippiMean_32f_C1R(const Ipp32f* pSrc, int srcStep, IppiSize roiSize, Ipp64f* pMean, IppHintAlgorithm hint);

Case 3: Masked operation on one-channel data

IppStatus ippiMean_<mod>(const Ipp<datatype>* pSrc, int srcStep, const Ipp8u* pMask, int maskStep, IppiSize roiSize, Ipp64f* pMean);

Supported values for mod:

8u_C1MR

8s_C1MR

16u_C1MR

32f_C1MR

Case 4: Operation on multi-channel integer data

IppStatus ippiMean_<mod>(const Ipp<datatype>* pSrc, int srcStep, IppiSize roiSize, Ipp64f mean[3]);

Supported values for mod:

8u_C3R	16u_C3R	16s_C3R
8u_AC4R	16u_AC4R	16s_AC4R

IppStatus ippiMean_<mod>(const Ipp<datatype>* pSrc, int srcStep, IppiSize roiSize, Ipp64f mean[4]);

Supported values for mod:

8u_C4R

16u_C4R

16s_C4R

Case 5: Operation on multi-channel floating-point data

IppStatus ippiMean_<mod>(const Ipp32f* pSrc, int srcStep, IppiSize roiSize, Ipp64f mean[3], IppHintAlgorithm hint);

Supported values for mod:

32f_C3R

32f_AC4R

IppStatus ippiMean_32f_C4R(const Ipp32f* pSrc, int srcStep, IppiSize roiSize, Ipp64f mean[4], IppHintAlgorithm hint);

Case 6: Masked operation on multi-channel data

IppStatus ippiMean_<mod>(const Ipp<datatype>* pSrc, int srcStep, const Ipp8u* pMask, int maskStep, IppiSize roiSize, int coi, Ipp64f* pMean);

Supported values for mod:

8u_C3CMR

8s_C3CMR

16u_C3CMR

32f_C3CMR

Parameters

pSrc	Pointer to the source image ROI.
srcStep	Distance in bytes between starts of consecutive lines in the source image.
pMask	Pointer to the mask image.
maskStep	Distance in bytes between starts of consecutive lines in the mask image.
roiSize	Size of the source ROI in pixels.
coi	Channel of interest (for color images only); can be 1, 2, or 3.
pMean	Pointer to the computed mean of pixel values.
mean	Array containing computed mean values for each channel of a multi-channel image.
hint	Option to select the algorithmic implementation of the function.

Description

The flavors of the function ippiMean that perform masked operations are declared in the ippcv.h file. All other function flavors are declared in the ippi.h file. This function operates with ROI (see Regions of Interest in Intel IPP). It computes the mean (average) of pixel values pMean for the source image pSrc. Computation algorithm is specified by the hint argument (see Table “Hint Arguments for Image Moment Functions”). For non-masked operations on a multi-channel image (Case 4, 5), the mean is computed over each channel and stored in the array mean. In the mask multi-channel mode (Case 6), the mean is computed for a single channel of interest specified by coi. The following code example shows how to use the ippiMean function:

Computing the Mean of Pixel Values

IppStatus mean( void ) {

   Ipp64f mean;

   Ipp8u x[5*4];

   IppiSize roi = {5,4};

   ippiSet_8u_C1R( 3, x, 5, roi );

   return ippiMean_8u_C1R( x, 5,
roi, &mean );

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr	Indicates an error when any of the specified pointers is `NULL`.
ippStsSizeErr	Indicates an error condition if roiSize has a field with zero or negative value.
ippStsStepErr	Indicates an error condition in mask mode, if srcStep or maskStep is less than roiSize.width * <pixelSize >.
ippStsNotEvenStepErr	Indicates an error condition in mask mode if steps for floating-point images cannot be divided by 4.
ippStsCOIErr	Indicates an error when coi is not 1, 2, or 3.