Manages a complete context for the Canny edge detector. More...

#include <eVision/EasyImage/ECannyEdgeDetector.h>

Collaboration diagram for eVision::ECannyEdgeDetector:

Public Member Functions
	ECannyEdgeDetector ()
	Constructs a ECannyEdgeDetector object initialized to its default values.
virtual	~ECannyEdgeDetector () throw ()
void	SetSmoothingScale (float scale)
	The scale of the features of interest.
float	GetSmoothingScale () const
	The scale of the features of interest.
void	ResetSmoothingScale ()
	Prevents the smoothing of the source image by a Gaussian filter.
void	SetThresholdingMode (eVision::ECannyThresholdingMode mode)
	Sets the mode of the hysteresis thresholding.
eVision::ECannyThresholdingMode	GetThresholdingMode () const
	Returns the mode of the hysteresis thresholding.
void	SetLowThreshold (float lowThreshold)
	Sets the low hysteresis threshold for a pixel to be considered as an edge.
float	GetLowThreshold () const
	Returns the low hysteresis threshold for a pixel to be considered as an edge.
void	SetHighThreshold (float highThreshold)
	Sets the high hysteresis threshold for a pixel to be considered as an edge.
float	GetHighThreshold () const
	Returns the high hysteresis threshold for a pixel to be considered as an edge.
void	Apply (const eVision::EROIBW8 &source, eVision::EROIBW8 &result)
	Apply the Canny edge detector on an image/ROI.
void	Apply (const eVision::EROIBW8 &source, const eVision::ERegion &region, eVision::EROIBW8 &result)
	Apply the Canny edge detector on an image/ROI.
void	Apply (const eVision::EROIBW8 &source, const eVision::ERegion &region, const eVision::EFrame &frame, eVision::EROIBW8 &result)
	Apply the Canny edge detector on an image/ROI.
	ECannyEdgeDetector (CppWrapperInternal::InternalConstructor)

Public Attributes
CppWrapperInternal::WrappedClass	wrappedClass_

Detailed Description

Manages a complete context for the Canny edge detector.

The Canny edge detector operates on a grayscale BW8 image and delivers a black-and-white BW8 image where pixels have only 2 possible values: 0 and 255. Pixels corresponding to edges in the source image are set to value 255 in the output image; The other pixels are set to value 0.

License(s): EasyImage

Constructor & Destructor Documentation

◆ ECannyEdgeDetector() [1/2]

eVision::ECannyEdgeDetector::ECannyEdgeDetector ( )

Constructs a ECannyEdgeDetector object initialized to its default values.

◆ ~ECannyEdgeDetector()

eVision::ECannyEdgeDetector::~ECannyEdgeDetector	(		)
throw	(	)

virtual

◆ ECannyEdgeDetector() [2/2]

eVision::ECannyEdgeDetector::ECannyEdgeDetector ( CppWrapperInternal::InternalConstructor )

Member Function Documentation

◆ Apply() [1/3]

void eVision::ECannyEdgeDetector::Apply	(	const eVision::EROIBW8 &	source,
		const eVision::ERegion &	region,
		const eVision::EFrame &	frame,
		eVision::EROIBW8 &	result )

Apply the Canny edge detector on an image/ROI.

Parameters

source	The source image/ROI.
region	The region on which to apply the method.
frame	The reference frame of the region.
result	The output image/ROI.

The output ROI must have the same size than the input ROI.

◆ Apply() [2/3]

void eVision::ECannyEdgeDetector::Apply	(	const eVision::EROIBW8 &	source,
		const eVision::ERegion &	region,
		eVision::EROIBW8 &	result )

Apply the Canny edge detector on an image/ROI.

Parameters

source	The source image/ROI.
region	The region on which to apply the method.
result	The output image/ROI.

The output ROI must have the same size than the input ROI.

◆ Apply() [3/3]

void eVision::ECannyEdgeDetector::Apply	(	const eVision::EROIBW8 &	source,
		eVision::EROIBW8 &	result )

Apply the Canny edge detector on an image/ROI.

Parameters

source	The source image/ROI.
result	The output image/ROI.

The output ROI must have the same size than the input ROI.

◆ GetHighThreshold()

float eVision::ECannyEdgeDetector::GetHighThreshold ( ) const

Returns the high hysteresis threshold for a pixel to be considered as an edge.

◆ GetLowThreshold()

float eVision::ECannyEdgeDetector::GetLowThreshold ( ) const

Returns the low hysteresis threshold for a pixel to be considered as an edge.

◆ GetSmoothingScale()

float eVision::ECannyEdgeDetector::GetSmoothingScale ( ) const

The scale of the features of interest.

This scale corresponds to the standard deviation of the Gaussian filter that is used to smooth the source image before the computation of the gradient, hereby selecting the scale of the features of interest.

If this scale is set to zero, no smoothing is achieved: The gradient is computed directly on the raw source image, speeding up the detector, but making the process much less reliable.

◆ GetThresholdingMode()

eVision::ECannyThresholdingMode eVision::ECannyEdgeDetector::GetThresholdingMode ( ) const

Returns the mode of the hysteresis thresholding.

◆ ResetSmoothingScale()

void eVision::ECannyEdgeDetector::ResetSmoothingScale ( )

Prevents the smoothing of the source image by a Gaussian filter.

Calling this method is equivalent to set ECannyEdgeDetector::SetSmoothingScale to zero. It disables the use of the Gaussian filter.

◆ SetHighThreshold()

void eVision::ECannyEdgeDetector::SetHighThreshold ( float highThreshold )

Sets the high hysteresis threshold for a pixel to be considered as an edge.

Parameters

highThreshold The high threshold.

◆ SetLowThreshold()

void eVision::ECannyEdgeDetector::SetLowThreshold ( float lowThreshold )

Sets the low hysteresis threshold for a pixel to be considered as an edge.

Parameters

lowThreshold The low threshold.

◆ SetSmoothingScale()

void eVision::ECannyEdgeDetector::SetSmoothingScale ( float scale )

The scale of the features of interest.

Parameters

scale The width of the Gaussian kernel, or zero if the Gaussian smoothing is disabled.

This scale corresponds to the standard deviation of the Gaussian filter that is used to smooth the source image before the computation of the gradient, hereby selecting the scale of the features of interest.

If this scale is set to zero, no smoothing is achieved: The gradient is computed directly on the raw source image, speeding up the detector, but making the process much less reliable.

◆ SetThresholdingMode()

void eVision::ECannyEdgeDetector::SetThresholdingMode ( eVision::ECannyThresholdingMode mode )

Sets the mode of the hysteresis thresholding.

Parameters

mode	The thresholding mode.

If the threshold mode is set to ECannyThresholdingMode::ECannyThresholdingMode_Absolute, the threshold values are interpreted as absolute thresholds. In this case, the thresholds must be strictly positive real values.

If the threshold mode is set to ECannyThresholdingMode::ECannyThresholdingMode_Relative, the thresholds are expressed as a fraction ranging from 0 to 1 of the maximum value of the gradient of the source image.

In either case, the low threshold must be less than the high threshold.

Member Data Documentation

◆ wrappedClass_

CppWrapperInternal::WrappedClass eVision::ECannyEdgeDetector::wrappedClass_

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ ECannyEdgeDetector() [1/2]

◆ ~ECannyEdgeDetector()

◆ ECannyEdgeDetector() [2/2]

Member Function Documentation

◆ Apply() [1/3]

◆ Apply() [2/3]

◆ Apply() [3/3]

◆ GetHighThreshold()

◆ GetLowThreshold()

◆ GetSmoothingScale()

◆ GetThresholdingMode()

◆ ResetSmoothingScale()

◆ SetHighThreshold()

◆ SetLowThreshold()

◆ SetSmoothingScale()

◆ SetThresholdingMode()

Member Data Documentation

◆ wrappedClass_