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 thanborderare 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 isNULL.
- ippStsSizeErr
- Indicates an error condition ifroiSizehas a field with zero or negative value; or ifmaxPeakCountis less than or equal to 0; or ifborderis less than 1 or greater than one of 0.5*roiSize.widthor of 0.5*roiSize.height.
- ippStsStepErr
- Indicates an error condition ifsrcStepis less thanroiSize.width*<pixelSize>.
- ippStsNotEvenStepErr
- Indicates an error condition ifsrcStepis 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;
}