Developer Reference

  • 2020
  • 07/15/2020
  • Public Content
Contents

HoughProbLine

Detects lines in the source image using the probabilistic Hough transform.

Syntax

IppStatus ippiHoughProbLine_8u32f_C1R(const Ipp8u*
pSrc
, int
srcStep
, IppiSize
roiSize
, int
threshold
, int
lineLength
, int
lineGap
, IppiPoint*
pLine
, int
maxLineCount
, int*
pLineCount
, Ipp8u*
pBuffer
, const IppiHoughProbSpec*
pSpec
);
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 source image ROI.
srcStep
Distance, in bytes, between the starting points of consecutive lines in the source image.
roiSize
Size of the source image ROI in pixels.
threshold
Minimum number of points that are required to detect the line.
lineLength
Minimum length of the line.
lineGap
Maximum length of the gap between lines.
pLine
Pointer to the detected line:
pLine[2*n]
indicates beginning of the line,
pLine[2*n+1]
indicates end of the line.
pLineCount
Number of detected lines.
maxLineCount
Number of elements in the destination buffer.
pBuffer
Pointer to the working buffer.
pSpec
Pointer to the specification structure.
Description
This function operates with ROI.
This function detects line segments of the binary
pSrc
image using the probabilistic Hough transform. Before using this function, compute the size of the working buffer and specification structure using the
ippiHoughProbGetSize
function and initialize the structure using the
ippiHoughProbLineInit
function.
This function implements the probabilistic Hough transform algorithm for line detection, described in [Matas00].
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error 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
maxLineCount
is less than or equal to 0.
ippStsStepErr
Indicates an error condition if
srcStep
has an illegal value.
ippStsBadArgErr
Indicates an error condition if
threshold
is less than or equal to 0.
ippStsDstSizeLessExpected
Indicates a warning if number of the detected lines is greater than the size of the destination buffer
maxLineCount
.

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 detecting lines in the source image using // the probabilistic Hough transform using Intel(R) Integrated Primitives (Intel(R) IPP) functions: // ippiHoughProbLineGetSize_8u_C1R // ippiHoughProbLineInit_8u32f_C1R // ippiHoughProbLine_8u32f_C1R #include <stdio.h> #include "ipp.h" #define WIDTH 800 /* image width */ #define HEIGHT 600 /* image height */ /* 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) 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) { int i = 0; IppStatus status = ippStsNoErr; Ipp8u* pSrc = NULL; /* Pointers to source images */ int srcStep = 0; /* Steps, in bytes, through the source images */ IppiSize roiSize = { WIDTH, HEIGHT }; /* Size of source ROI in pixels */ int bufferSize = 0, specSize = 0;/* Size of the working buffer and spec structure */ Ipp8u *pBuffer = NULL; IppiHoughProbSpec* pSpec = NULL; IppiPoint pLineP[128]; /* Pointer to output array of detected lines */ int threshold = 20, lineLength = 40, ineGap = 4, maxLineCount = 128; IppPointPolar delta = { 1, (Ipp32f)IPP_PI / 180.f / 3.f }; /* Step of discretization */ int lineCount = 0; /* Number of detected lines. */ pSrc = ippiMalloc_8u_C1(roiSize.width, roiSize.height, &srcStep); check_sts( status = ippiSet_8u_C1R(0, pSrc, srcStep, roiSize) ) /* Zero image */ for (i = 0; i<70; i++) { /* Draw line (100,100)-(170,170) */ pSrc[(i + 100)*srcStep + i + 100] = 255; } /* Compute the size of the working buffer and spec structure */ check_sts( status = ippiHoughProbLineGetSize_8u_C1R(roiSize, delta, &specSize, &bufferSize) ) pBuffer = (Ipp8u*)ippsMalloc_8u(bufferSize); pSpec = (IppiHoughProbSpec*)ippsMalloc_8u(specSize); /* Initialize the specification structure */ check_sts( status = ippiHoughProbLineInit_8u32f_C1R(roiSize, delta, ippAlgHintNone, pSpec) ) /* Detect lines in the source image using the probabilistic Hough transform. */ check_sts( status = ippiHoughProbLine_8u32f_C1R(pSrc, srcStep, roiSize, threshold, lineLength, ineGap, pLineP, maxLineCount, &lineCount, pBuffer, pSpec) ) EXIT_MAIN ippsFree(pBuffer); ippiFree(pSrc); ippsFree(pSpec); printf("Exit status %d (%s)\n", (int)status, ippGetStatusString(status)); return (int)status; }

Product and Performance Information

1

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