Intel® Integrated Performance Primitives Developer Guide and Reference

ID 790148
Date 11/07/2023
Public

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Document Table of Contents

ThresholdAdaptiveBox

Performs adaptive thresholding with the Box method.

Syntax

IppStatus ippiThresholdAdaptiveBox_8u_C1R(const Ipp8u* pSrc, int srcStep, Ipp8u* pDst, int dstStep, IppiSize roiSize, IppiSize maskSize, Ipp32f delta, Ipp8u valGT, Ipp8u valLE, IppiBorderType borderType, Ipp8u borderValue, Ipp8u* pBuffer);

IppStatus ippiThresholdAdaptiveBox_8u_C1IR(Ipp8u* pSrcDst, int srcDstStep, IppiSize roiSize, IppiSize maskSize, Ipp32f delta, Ipp8u valGT, Ipp8u valLE, IppiBorderType borderType, Ipp8u borderValue, Ipp8u* pBuffer);

Include Files

ippi.h

Domain Dependencies

Headers: ippcore.h, ippvm.h, ipps.h

Libraries: ippcore.lib, ippvm.lib, ipps.lib

Parameters

pSrc
Pointer to the source image ROI.
srcStep
Distance, in bytes, between the starting points of consecutive lines in the source image.
pDst
Pointer to the destination image ROI.
dstStep
Distance, in bytes, between the starting points of consecutive lines in the destination image.
pSrcDst
Pointer to the source and destination image ROI (for the in-place function).
srcDstStep
Distance, in bytes, between the starting points of consecutive lines in the source and destination image (for the in-place function).
roiSize
Size of the destination image ROI, in pixels.
maskSize

Size of the kernel that is used to calculate a threshold level. Width and height of maskSize must be equal and odd.

delta
Value for threshold calculation.
valGT
Output pixel if the source pixel value is more than threshold.
valLE
Output pixel if the source pixel value is less than, or equal to threshold.
borderType

Type of border. Possible values are:

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.

Mixed borders are also supported. They can be obtained by the bitwise operation OR between ippBorderRepl or ippBorderConst and the following flags:

  • ippBorderInMemTop
  • ippBorderInMemBottom
  • ippBorderInMemLeft
  • ippBorderInMemRight
Each of these flags means that for the corresponding border the outside pixels of the source image are in memory.

borderValue

Constant value(s) to assign to pixels of the constant border. This parameter is applicable only to the ippBorderConst border type.

pBuffer
Pointer to the work buffer. To calculate the size of the temporary buffer, use the ThresholdAdaptiveBoxGetBufferSize function.

Description

This function performs adaptive thresholding of the source image ROI using the Box method. Output pixels are calculated according to the following formulas:

pDst(x,y) = valGT, if pSrc(x,y) > T(x,y)

pDst(x,y) = valLE, if pSrc(x,y) <= T(x,y)

where

T(x,y) is a mean of the maskSize.width*maskSize.height neighborhood of a (x, y) pixel minus delta.

Before using this function, compute the size of the external work buffer using the ThresholdAdaptiveBoxGetBufferSize function.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error when pSrc, pDst, pSrcDst, or pBuffer is NULL.

ippStsSizeErr

Indicates an error when roiSize has a field with a zero or negative value.

ippStsMaskSizeErr

Indicates an error when maskSize has a field with a zero or negative value, or fields of maskSize are not equal.

ippStsBorderErr

Indicates an error when borderType has an illegal value.

Example

The code example below demonstrates how to use the ippiThresholdAdaptiveBox_8u_C1R and ThresholdAdaptiveBoxGetBufferSize functions.

IppStatus threshold_adaptive_box_8u_c1( void ) {
    Ipp8u pSrc[8*8] =
    {
          0, 255,   1, 254,   2, 253,   3, 252,
        251,   4, 250,   5, 249,   6, 248,   7,
          8, 247,   9, 246,  10, 245,  11, 244,
        243,  12 , 242, 13, 241,  14, 240,  15,
         16, 239,  17, 238,  18, 237,  19, 236,
        235,  20, 234,  21, 233,  22, 232,  23,
         24, 231,  25, 230,  26, 229,  26, 228,
        227,  27, 226,  28, 225,  29, 224,  30
    };
    Ipp8u    pDst[8*8];
    IppiSize roiSize = {8, 8};
    IppiSize maskSize = {3, 3};
    IppiBorderType borderType = ippBorderConst;
    int     srcStep = 8 * sizeof(Ipp8u);
    int     dstStep = 8 * sizeof(Ipp8u);
    int     bufferSize;
    IppStatus status;
    Ipp32f  delta = 0.5f;
    Ipp8u   valGT = 254;
    Ipp8u   valLE = 1;
    Ipp8u   *pBuffer;

    ippiThresholdAdaptiveBoxGetBufferSize(roiSize, maskSize, ipp8u, 1, &bufferSize);
    pBuffer = ippsMalloc_8u(bufferSize);
    ippiThresholdAdaptiveBox_8u_C1R(pSrc, srcStep, pDst, dstStep, roiSize, maskSize, delta, valGT, valLE, borderType, 33, pBuffer);
    ippsFree(pBuffer);
    return status;
}

pDst after function execution:

   1 254   1 254   1 254   1 254
 254   1 254   1 254   1 254   1
   1 254   1 254   1 254   1 254
 254   1 254   1 254   1 254   1
   1 254   1 254   1 254   1 254
 254   1 254   1 254   1 254   1
   1 254   1 254   1 254   1 254
 254   1 254   1 254   1 254   1

See Also