Intel IPP Integration Wrappers Developer Guide and Reference

Download PDF
ID 751823
Date 1/18/2023
Public
Document Table of Contents
Document Table of Contents x
Integration Wrappers for Intel(R) Integrated Performance Primitives Developer Guide and Reference
Integration Wrappers for Intel(R) Integrated Performance Primitives Developer Guide and Reference x
Introducing Integration Wrappers for Intel® Integrated Performance Primitives Getting Help and Support Overview Getting Started C Reference C++ Reference Bibliography Notices and Disclaimers
Overview x
Key Features Architecture Conventions Tiling and Threading
Getting Started x
Checking Your Installation Configuring Your Build Environment Finding Documentation for Integration Wrappers Sources
C Reference x
Core Functionality Signal Processing Image Processing
Core Functionality x
Library Scope Initialization and Control Utility Functions
Library Scope Initialization and Control x
iwGetLibVersion iwSetThreadsNum iwGetThreadsNum iwGetThreadsNumDefault iwGetStatusString
Utility Functions x
iwTypeToSize iwTypeIsFloat iwTypeIsSigned iwTypeGetMax iwTypeGetMin iwTypeGetRange iwValueSaturate iwValueAbsToRel iwValueRelToAbs iwRangeWeightCorrector iwAtomic_AddInt Thread Local Storage
Thread Local Storage x
IwTls Structure iwTls_Init iwTls_Set iwTls_Get iwTls_Release iwTls_ReleaseData
Signal Processing x
Signal Processing Structures Vector Tiling Functions Signal Transforms
Vector x
iwsShiftPtr iwsVector_Init iwsVector_InitExternal iwsVector_InitExternalConst iwsVector_Alloc iwsVector_Release iwsVector_GetPtr iwsVector_GetPtrConst iwsVector_BorderAdd iwsVector_BorderSub iwsVector_BorderSet iwsVector_RoiSet iwsVector_GetRoiVector
Tiling Functions x
iwsTile_SetRoi
Signal Transforms x
iwsDCT
Image Processing x
Image Processing Structures Utility Functions Basic Operations Arithmetic Operations Filtering Functions Image Geometry Transforms Color Conversion
Utility Functions x
iwiShiftPtr iwiShiftPtrConst iwiSizeToBorderSize iwiMaskToSize iwiSizeSymToBorderSize Image Tiling Functions
Image x
iwiImage_Init iwiImage_InitExternal iwiImage_InitExternalConst iwiImage_Alloc iwiImage_Release iwiImage_GetPtr iwiImage_GetPtrConst iwiImage_BorderAdd iwiImage_BorderSub iwiImage_BorderSet iwiImage_RoiSet iwiImage_GetRoiImage
Tiling Functions x
iwiTile_GetTileBorder iwiTile_GetMinTileSize iwiTile_CorrectBordersOverlap Basic Tiling API Pipeline Tiling API
Basic Operations x
iwiCopyChannel iwiCopy iwiCopyMerge iwiCopySplit iwiCopyMakeBorder iwiScale iwiScale_GetScaleVals iwiSetChannel iwiSet iwiSwapChannels
Arithmetic Operations x
iwiAdd iwiAddC iwiSub iwiSubC iwiMul iwiMulC iwiDiv iwiDivC
Filtering Functions x
Filtering Structures and Enumerators iwiFilter iwiFilterBox iwiFilterCanny Syntax Parameters Auxiliary Arguments Description Return Values iwiFilterCannyDeriv iwiFilterSobel iwiFilterScharr iwiFilterLaplacian iwiFilterGaussian iwiFilterMorphology iwiFilterMorphology_GetBorderSize iwiFilterBilateral
Image Geometry Transforms x
iwiMirror iwiMirror_GetSrcRoi iwiRotate iwiRotate_GetDstSize Resize WarpAffine
Resize x
Structures and Enumerators iwiResize_SetDefaultParams iwiResize iwiResize_Free iwiResize_InitAlloc iwiResize_Process iwiResize_GetSrcRoi iwiResize_GetBorderSize
WarpAffine x
Edge Smoothing Structures and Enumerators iwiWarpAffine_SetDefaultParams iwiWarpAffine iwiWarpAffine_Free iwiWarpAffine_InitAlloc iwiWarpAffine_Process
Color Conversion x
IwColorFmt Enumerator iwiColorToChannels iwiColorToPlanes iwiColorGetPlaneSize iwiColorConvert
C++ Reference x
Core Functionality Signal Processing Image Processing
Signal Processing x
Basic Classes Signal Transforms
Signal Transforms x
iwsDCT
Image Processing x
Basic Classes Basic Operations Arithmetic Operations Filtering Functions Image Geometry Transforms Color Conversion
Basic Operations x
iwiCopyChannel iwiCopy iwiCopyMerge iwiCopySplit iwiCopyMakeBorder iwiSwapChannels iwiScale iwiScale_GetScaleVals iwiSetChannel iwiSet
Arithmetic Operations x
iwiAdd iwiAddC iwiSub iwiSubC iwiMul iwiMulC iwiDiv iwiDivC
Filtering Functions x
Filtering Structures and Enumerators iwiFilter iwiFilterBox iwiFilterCanny iwiFilterCannyDeriv iwiFilterSobel iwiFilterBilateral iwiFilterScharr iwiFilterLaplacian iwiFilterMorphology iwiFilterMorphology_GetBorderSize FilterGaussian
FilterGaussian x
class IwiFilterGaussianParams class IwiFilterGaussian iwiFilterGaussian
Image Geometry Transforms x
iwiMirror_GetSrcRoi iwiMirror_GetDstSize iwiMirror Resize WarpAffine
Resize x
class IwiResizeParams class IwiResize
WarpAffine x
class IwiWarpAffineParams class IwiWarpAffine
Color Conversion x
iwiColorConvert
Integration Wrappers for Intel(R) Integrated Performance Primitives Developer Guide and Reference

iwiFilterCanny

Syntax

typedef struct _IwiFilterCannyParams
{
    IppiDifferentialKernel  kernel; 
    IppiMaskSize            kernelSize; 
    IppNormType             norm;
} IwiFilterCannyParams;
static IW_INLINE void iwiFilterCanny_SetDefaultParams(
    IwiFilterCannyParams *pParams 
)

IW_DECL(IppStatus) iwiFilterCanny(
    const IwiImage             *pSrcImage,   
    IwiImage                   *pDstImage, 
    Ipp32f                      treshLow,   
    Ipp32f                      treshHigh,  
    const IwiFilterCannyParams *pAuxParams,
    IppiBorderType              border,     
    const Ipp64f               *pBorderVal  
);

Parameters

pSrcImage

Pointer to the source image.

pDstImage

Pointer to the destination image.

treshLow

Lower threshold for edges detection.

treshHigh

Upper threshold for edges detection.

pAuxParams

 Pointer to the auxiliary parameters structure. If NULL, default parameters are used.

border

Extrapolation algorithm for out of image pixels processing. Supported values:

ippBorderConst

 Values of all border pixels are set to a constant.

ippBorderRepl

 Border is replicated from the edge pixels.

ippBorderInMem

 Border is obtained from the source image pixels in memory.

ippBorderMirror

 Border pixels are mirrored from the source image boundary pixels.

pBorderVal

Pointer to an array of values to assign to pixels of the constant border, one element of the array for each channel of the image. This parameter is applicable only to the ippBorderConst border type and can be NULL for other border types.

Auxiliary Arguments

Argument Default Value Description

kernel

ippFilterSobel

Type of the differential kernel. Supported values: ippFilterSobel, ippFilterScharr.
kernelSize ippMskSize3x3 Size of the filter kernel. Supported values for ippFilterSobel: ippMskSize3x3, ippMskSize5x5; for ippFilterScharr: ippMskSize3x3.
norm ippNormL2 Normalization mode. Supported values: ippNormL1 and ippNormL2.

Description

This function applies the Canny edge detector [Canny86] to the source image. The detector uses a grayscale image as an input and outputs a black-and-white image, where non-zero pixels mark detected edges. The algorithm consists of three stages described below.

Stage 1: Differentiation

The image data is differentiated in x and y directions. From the computed x and y gradient components, Canny edge detector functions calculate the magnitude and angle of the gradient vector.

Stage 2: Non-maximum Suppression

With the rate of intensity change found at each point in the image, edges must be placed at the points of maximum values of gradient magnitude. It is preferable to suppress non-maximum points that are perpendicular to the edge direction, rather than parallel to the edge direction, as the edge is strong along an extended contour.

The algorithm starts off with sorting the direction of gradient to one of four sectors shown in the figure below.

Gradient Sectors

The algorithm passes a 3x3 neighborhood across the magnitude array. At each point, the center element of the neighborhood is compared with its two neighbors along the line of the gradient given by the sector value. If the central value is not greater than the neighbors, it is suppressed.

Stage 3: Edge Thresholding

The Canny operator uses the so-called “hysteresis” thresholding. Most thresholders use a single threshold limit, which means that if the edge values fluctuate above and below this value, the line appears broken. This phenomenon is commonly referred to as “streaking”. Hysteresis counters streaking by setting an upper and lower edge value limit. Considering a line segment, if a value lies above the upper threshold limit, it is immediately accepted. If the value lies below the low threshold, it is rejected. Points which lie between the two limits are accepted if they are connected to pixels which are also accepted. The likelihood of streaking is small, since the line segment points must fluctuate above the upper limit and below the lower limit for streaking to occur.

J.Canny recommends the ratio of high to low limit be in the range two or three to one, based on predicted signal-to-noise ratios.

This function supports the following features:

Feature Support
Internal threading No
Manual tiling No
IwiTile simple tiling No
IwiTile pipeline tiling No

Return Values

ippStsNoErr

No errors.

ippStsMaskSizeErr

The kernel value is illegal.

ippStsDataTypeErr

The dataType value is illegal.

ippStsNumChannelsErr

The channels value is illegal.

ippStsNotEvenStepErr

The srcStep and/or dstStep value is not divisible by size of elements.

ippStsBorderErr

The border value is illegal.

ippStsNoMemErr

Failed to allocate memory.

ippStsSizeErr

Values of the size fields are illegal.

ippStsInplaceModeNotSupportedErr

In-place operation is not supported: pSrc is equal to pDst.

ippStsNullPtrErr

At least one of the pointers (except pTile) is NULL.
Parent topic: Filtering Functions
Level Two Title