Developer Reference

  • 2021
  • 01/15/2021
  • Public Content
Contents

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
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
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
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
16u_C3CMR
32f_C3CMR
Include Files
ippi.h
ippcv.h
Domain Dependencies
Flavors declared in
ippi.h
:
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
Flavors declared in
ippcv.h
:
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
,
ippi.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
,
ippi.lib
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
.
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.

Example

The code example below shows how to use the
ippiMean
function.
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 ); }

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.