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cvHoughLines

Finds lines in a binary image using standard Hough transform.

Name	Type	Range	Description
inImage	Image		UINT8, single-channel input image.
inRho	Real	0.0 -	Distance resolution of the accumulator in pixels.
inTheta	Real	0.0 -	Angle resolution of the accumulator in degrees.
inThreshold	Integer	1 -	Accumulator threshold parameter.
inSrn	Real		For the multi-scale Hough transform, it is a divisor for the distance resolution rho. The coarse accumulator distance resolution is rho and the accurate accumulator resolution is rho/srn . If both srn=0 and stn=0 , the classical Hough transform is used. Otherwise, both these parameters should be positive.
inStn	Real		For the multi-scale Hough transform, it is a divisor for the distance resolution theta.
outLines	Line2D Array		Output array of lines.

Description

The operation detects straight edges in the inImage using the Hough Transform approach and treats them as infinite lines. Input image is treated as binary image. Therefore all non-zero pixels are assumed to be edges.

Examples

cvHoughLines performed on the sample image with inRho = 2.0, inTheta = 10.0, inThreshold = 250.

Remarks

Note, that non-zero pixels are treated as edge, which is different approach from the one in cvHoughCircles filter. To obtain edges image, one can use i.e. cvCanny filter.

Errors

This filter can throw an exception to report error. Read how to deal with errors here: Error Handling

Error type	Description
DomainError	Input image must be UINT8 single-channel in cvHoughLines.
DomainError	inRho, inTheta and inThreshold must be positive in cvHoughLines.

Complexity Level