HoughLine

Detects straight lines in the source image.

Syntax

IppStatus ippiHoughLine_8u32f_C1R(const Ipp8u* pSrc, int srcStep, IppiSize roiSize, IppPointPolar delta, int threshold, IppPointPolar* pLine, int maxLineCount, int* pLineCount, Ipp8u* pBuffer);

Parameters

pSrc
Pointer to the source image ROI.
srcStep
Distance in bytes between starts of consecutive lines in the source image.
roiSize
Size of source image ROI in pixels.
delta
Step of discretization ( delta.rho - radial increment, delta.theta - angular increment).
threshold
Minimum number of points that are required to detect the line.
pLine
Pointer to the destination buffer for lines.
maxLineCount
Number of elements of the destination buffer.
pBuffer
Pointer to the working buffer.

Description

The function ippiHoughLine is declared in the ippcv.h file. It operates with ROI (see Regions of Interest in Intel IPP).

In the binarised source image pSrc, the function performs detection of the straight line defined by the equation given at the beginning of section Hough Transform. The level of discretization delta is specified as the input parameters. The performance and effectiveness of the function is strongly depends on this parameter. The function requires the external working buffer pBuffer whose size should be computed previously using the function ippiHoughLineGetSize.

Caution iconCaution

The value of the parameter delta must not be greater than the value of the parameter delta set when the size of the working buffer is computed.

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; or delta.rho is less than 0, or greater than sum of the width and height of the ROI; or delta.theta is less than 0, or greater than p.

ippStsDstSizeLessExpected

Indicates a warning if number of the detected lines is greater thean the size of the destination buffer maxLineCount.

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