NormDiff

Computes the L1- norm of differences between pixel values of two images.

Syntax

Case 1: Operation on one-channel integer data

IppStatus ippiNormDiff_L1_<mod>(const Ipp<datatype>* pSrc1, int src1Step, const Ipp<datatype>* pSrc2, int src2Step, IppiSize roiSize, Ipp64f* pValue);

Supported values for mod:

8u_C1R

16u_C1R

16s_C1R

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

IppStatus ippiNormDiff_L1_32f_C1R(const Ipp32f* pSrc1, int src1Step, const Ipp32f* pSrc2, int src2Step, IppiSize roiSize, Ipp64f* pValue, IppHintAlgorithm hint);

Case 3: Masked operation on one-channel data

IppStatus ippiNormDiff_L1_<mod>(const Ipp<datatype>* pSrc1, int src1Step, const Ipp32f* pSrc2, int src2Step, const Ipp8u* pMask, int maskStep, IppiSize roiSize, Ipp64f* pNorm);

Supported values for mod:

8u_C1MR

8s_C1MR

16u_C1MR

32f_C1MR

Case 4: Operation on multi-channel integer data

IppStatus ippiNormDiff_L1_<mod>(const Ipp<datatype>* pSrc1, int src1Step, const Ipp<datatype>* pSrc2, int src2Step, IppiSize roiSize, Ipp64f value[3]);

Supported values for mod:

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

IppStatus ippiNormDiff_L1_<mod>(const Ipp<datatype>* pSrc1, int src1Step, const Ipp<datatype>* pSrc2, int src2Step, IppiSize roiSize, Ipp64f value[4]);

Supported values for mod:

8u_C4R

16u_C4R

16s_C4R

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

IppStatus ippiNormDiff_L1_<mod>(const Ipp32f* pSrc1, int src1Step, const Ipp32f* pSrc2, int v, IppiSize roiSize, Ipp64f value[3], IppHintAlgorithm hint);

Supported values for mod:

32f_C3R

32f_AC4R

IppStatus ippiNormDiff_L1_32f_C4R(const Ipp32f* pSrc1, int src1Step, const Ipp32f* pSrc2, int src2Step, IppiSize roiSize, Ipp64f value[4], IppHintAlgorithm hint);

Case 6: Masked operation on multi-channel data

IppStatus ippiNormDiff_L1_<mod>(const Ipp<datatype>* pSrc1, int src1Step, const Ipp32f* pSrc2, int src2Step, const Ipp8u* pMask, int maskStep, IppiSize roiSize, int coi, Ipp64f* pNorm);

Supported values for mod:

8u_C3CMR

8s_C3CMR

16u_C3CMR

32f_C3CMR

Parameters

pSrc1, pSrc2	Pointers to the source images ROI.
src1Step, src2Step	Distance in bytes between starts of consecutive lines in the source images.
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.
pValue	Pointer to the computed L1- norm of difference between pixel values.
value	An array containing the computed L1- norms of difference between channel values in case of multi-channel data.
pNorm	Pointer to the computed norm value in the mask mode.
hint	Option to select the algorithmic implementation of the function.

Description

The flavors of the function ippiNormDiff_L1 that perform masked operation are declared in the ippcv.h file. All other function flavors are declared in the ippi.h file. The function operates with ROI (see Regions of Interest in Intel IPP). It computes the L1-norm pValue (pNorm in the mask mode) of differences between pixel values of the two source image buffers pSrc1 and pSrc2. This norm is defined as the sum of absolute values of differences:

norm = Σ |pSrc1-pSrc2|

Computation algorithm is specified by the hint argument (see Table “Hint Arguments for Image Moment Functions”). In the mask mode, the computation is done over pixels selected by nonzero mask values.

For non-masked operations on multi-channel images (Case 4,5), the norm is computed separately for each pair of the corresponding channels and stored in the array value .

In the mask multi-channel mode (Case 6), the norm is computed for a single channel of interest specified by coi.

Example “Using the function ippiNormDiff_L1” shows how to use the function ippiNormDiff_L1_8u_C1R.

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 src1Step, src2Step, 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.

Using the function ippiNormDiff_L1

void func_normdiff_l1()

    Ipp8u pSrc1[8*4];

    Ipp8u pSrc2[8*4];

    Ipp64f Value;

    int src1Step = 8;

    int src2Step = 8;

    IppiSize roi = {8,4};

    IppiSize roiSize = {5,4};

    ippiSet_8u_C1R(1, pSrc1, src1Step, roi);

    ippiSet_8u_C1R(2, pSrc2, src2Step, roi);

    ippiNormDiff_L1_8u_C1R( pSrc1, src1Step, pSrc2, src2Step, roiSize, &Value);

Result -> 20.0