Intel® Integrated Performance Primitives Developer Reference

Developer Reference

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

FilterSobelHorizBorder

Filters an image using a horizontal Sobel filter.

Syntax

IppStatus ippiFilterSobelHorizBorder_<mod>(const Ipp<srcDatatype>*
pSrc
, int
srcStep
, Ipp<dstDatatype>*
pDst
, int
dstStep
, IppiSize
dstRoiSize
, IppiMaskSize
mask
, IppiBorderType
borderType
, Ipp<srcDatatype>
borderValue
, Ipp8u*
pBuffer
);
Supported values for
mod
:
8u16s_C1R
16s_C1R
32f_C1R
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.
dstRoiSize
Size of the source and destination ROI in pixels.
mask
Predefined mask of
IppiMaskSize
. Possible values are
ippMskSize3x3
 or
ippMskSize5x5
.
borderType
Type of border. Possible values are:
ippBorderConst
Values of all border pixels are set to constant.
ippBorderRepl
Border is replicated from the edge pixels.
ippBorderMirror
Mirrored border is used.
ippBorderMirrorR
Mirrored border with replication is used.
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 any of the
ippBorderRepl
,
ippBorderConst
,
ippBorderMirror
, or
ippBorderMirrorR
 values and the
ippBorderInMemTop
,
ippBorderInMemBottom
,
ippBorderInMemLeft
,
ippBorderInMemRight
 values.
borderValue
Constant value to assign to pixels of the constant border. This parameter is applicable only to the
ippBorderConst
 border type.
pBuffer
Pointer to the work buffer.
Description
Before using this function, you need to compute the size of the work buffer
pBuffer
 using the
FilterSobelHorizBorderGetBufferSize
 function.
This function operates with ROI.
This function applies a horizontal Sobel filter to the
pSrc
 source image ROI. The size of the source image ROI is equal to the destination image ROI size
dstRoiSize
. The values of border pixels are assigned in accordance with the
borderType
 and
borderValue
 parameters. The kernel of the filter is a matrix of 3x3 or 5x5 size depending on the
mask
 value. The kernels have the following values:
                              1   4   6   4   1
   1   2   1                  2   8   12  8   2
   0   0   0       or         0   0   0   0   0
  -1  -2  -1                 -2  -8  -12  -8  -2
                             -1  -4   -6  -4  -1
The anchor cell is the center cell of the kernel, highlighted in red.
This filter enhances horizontal edges of an image.
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error when one of the specified pointers is
NULL
.
ippStsSizeErr
Indicates an error when
dstRoiSize
 is negative, or equal to zero.
ippStsStepErr
Indicates an error when
srcStep
 or
dstStep
 is negative, or equal to zero.
ippStsNotEvenStepErr
Indicates an error when one of the step values is not divisible by 4 for floating-point images, or by 2 for short-integer images.
ippStsBorderErr
Indicates an error when
borderType
 has an illegal value.

Example

The code example below demonstrates how to use the
ippiFilterSobelHorizBorderGetBufferSize
 and
ippiFilterSobelHorizBorder_8u16s_C1R
 functions to filter an image with the Sobel horizontal kernel.
IppStatus fix_sobelhoriz_8u16( void ) {
    Ipp8u pSrc[9*8] =
	    {
	        0, 1, 2, 120, 121, 122, 50, 51, 52,
	        1, 2, 3, 121, 122, 123, 52, 52, 53,
	        3, 4, 5, 130, 131, 132, 63, 64, 65,
	        4, 5, 6, 131, 132, 133, 64, 65, 66,
	        5, 6, 7, 132, 133, 134, 65, 66, 67,
                  8, 7, 6, 134, 133, 132, 67, 66, 65,
                  7, 6, 5, 133, 132, 131, 66, 65, 64,
                  6, 5, 4, 132, 131, 130, 65, 64, 63
          };
    Ipp16s  pDst[8*7];
    Ipp8u   *pBuffer;
    IppiSize roiSize = {8, 7};
    IppiBorderType borderType = ippBorderRepl | ippBorderInMemTop | ippBorderInMemRight;
    int    srcStep = 9 * sizeof(Ipp8u);
    int    dstStep = 8 * sizeof(Ipp16s);
    int    bufferSize;
    IppStatus status;
    ippiFilterSobelHorizBorderGetBufferSize(roiSize, ippMskSize3x3, ipp8u, ipp16s, 1, &bufferSize);
    pBuffer = ippsMalloc_8u(bufferSize);
    status = ippiFilterSobelHorizBorder_8u16s_C1R(pSrc + srcStep, srcStep, pDst, dstStep, roiSize, ippMskSize3x3,
             borderType, 0, pBuffer);
    ippsFree(pBuffer);
    return status;
}
The result is as follows:
pDst -->
 12  12  19  33  40  43  49  52 
 12  12  19  33  40  42  47  51 
  8   8   8   8   8   8   8   8 
 14   8   5   7   4   2   6   4 
  6   0  -3  -1  -4  -6  -2  -4 
 -8  -8  -8  -8  -8  -8  -8  -8 
 -4  -4  -4  -4  -4  -4  -4  -4

Product and Performance Information

1

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