Developer Reference

  • 2020
  • 10/21/2020
  • Public Content
Contents

FindPeaks3x3

Finds coordinates of peaks (maximums or minimums) with absolute value exceeding threshold value.

Syntax

IppStatus ippiFindPeaks3x3_32s_C1R(const Ipp32s*
pSrc
, int
srcStep
, IppiSize
roiSize
, Ipp32s
threshold
, IppiPoint*
pPeak
, int
maxPeakCount
, int*
pPeakCount
, IppiNorm
norm
, int
border
, Ipp8u*
pBuffer
);
IppStatus ippiFindPeaks3x3_32f_C1R(const Ipp32f*
pSrc
, int
srcStep
, IppiSize
roiSize
, Ipp32f
threshold
, IppiPoint*
pPeak
, int
maxPeakCount
, int*
pPeakCount
, IppiNorm
norm
, int
border
, Ipp8u*
pBuffer
);
Include Files
ippcv.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
,
ippi.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
,
ippi.lib
Parameters
pSrc
Pointer to the first source image ROI.
srcStep
Distance in bytes between starts of consecutive lines in the first source image.
roiSize
Size of the image ROI in pixels.
threshold
Threshold value.
pPeak
Pointer to the coorditanes peaks [
maxPeakCount
].
maxPeakCount
Maximum number of peaks.
pPeakCount
Pointer to the number of the detected peaks.
border
Border value, only pixel with distance from the edge of the image greater than
border
are processed.
norm
Specifies type of the norm to form the mask for extremum search:
ippiNormInf
Infinity norm (8-connectivity, 3x3 rectangular mask);
ippiNormL1
L1 norm (4-connectivity, 3x3 cross mask).
pBuffer
Pointer to the working buffer.
Description
This function operates with ROI (see Regions of Interest in Intel IPP).
This function detects local maximum and minimum pixels in the source image:
and stores their coordinates in the
pPeak
array
pPeak
[m].x = jm,
pPeak
[m].y = im, m = 0, ...
pPeakCount
[0],
pPeakCount[0]
maxPeakCount
The neighborhood
O
(
i
,
j
) for the extremum search is defined by the parameter
norm
. The number of detected extremums is returned in
pPeakCount[0]
. The operation is stopped when the
maxPeakCount
extremums are found.
The function requires the working buffer
pBuffer
whose size should be computed by the function ippiFindPeaks3x3GetBufferSize beforehand.
Return Values
ippStsNoErr
Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr
Indicates an error condition if one of the specified pointers is
NULL
.
ippStsSizeErr
Indicates an error condition if
roiSize
has a field with zero or negative value; or if
maxPeakCount
is less than or equal to 0; or if
border
is less than 1 or greater than one of 0.5*
roiSize.width
or of 0.5*
roiSize.height
.
ippStsStepErr
Indicates an error condition if
srcStep
is less than
roiSize.width*<pixelSize>
.
ippStsNotEvenStepErr
Indicates an error condition if
srcStep
is not divisible by 4.

Example



    
/******************************************************************************* * Copyright 2015-2020 Intel Corporation. * * This software and the related documents are Intel copyrighted materials, and * your use of them is governed by the express license under which they were * provided to you (License). Unless the License provides otherwise, you may not * use, modify, copy, publish, distribute, disclose or transmit this software or * the related documents without Intel's prior written permission. * * This software and the related documents are provided as is, with no express * or implied warranties, other than those that are expressly stated in the * License. *******************************************************************************/ // A simple example of finding coordinates of peaks // ippiFindPeaks3x3GetBufferSize_32f_C1R // ippiFindPeaks3x3_32f_C1R #include <stdio.h> #include "ipp.h" #define WIDTH 128 /* Image width */ #define HEIGHT 128 /* Image height */ #define KERSIZE 3 /* Kernel size */ /* Next two defines are created to simplify code reading and understanding */ #define EXIT_MAIN exitLine: /* Label for Exit */ #define check_sts(st) if((st) != ippStsNoErr) goto exitLine; /* Go to Exit if Intel(R) Integrated Primitives (Intel(R) IPP) function returned status different from ippStsNoErr */ /* Results of ippMalloc() are not validated because Intel(R) IPP functions perform bad arguments check and will return an appropriate status */ int main(void) { IppStatus status = ippStsNoErr; Ipp32f *pSrc = NULL; /* initial image */ Ipp8u *pBuffer = NULL; /* working buffer */ IppiPoint *pPeak = NULL; /* array of peaks */ IppiSize roiSize = { WIDTH, HEIGHT }; /* image size */ int srcStep = 0; /* row step in bytes */ int bufSize = 0; /* working buffer size */ int maxPeaks=500; /* max peaks number for image */ int peakCount = 0; /* peaks number for image */ Ipp32f threshold=0.02f; /* peak threshold */ Ipp32s borderValue=40; /* Border Value */ pSrc = ippiMalloc_32f_C1(roiSize.width, roiSize.height, &srcStep); check_sts( status = ippiFindPeaks3x3GetBufferSize_32f_C1R(roiSize.width,&bufSize) ) pBuffer = ippsMalloc_8u(bufSize); pPeak = (IppiPoint*)ippsMalloc_8u(maxPeaks*sizeof(IppiPoint)); check_sts( status = ippiFindPeaks3x3_32f_C1R(pSrc,srcStep,roiSize,threshold,pPeak,maxPeaks, &peakCount,ippiNormL1,borderValue,pBuffer) ) EXIT_MAIN ippsFree(pBuffer); ippsFree(pPeak); ippiFree(pSrc); printf("Exit status %d (%s)\n", (int)status, ippGetStatusString(status)); return status; }

Product and Performance Information

1

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Notice revision #20110804