DirectGraphicalModels::fex::CGradient Class Reference

Gradient feature extraction class. More...

#include <Gradient.h>

Inheritance diagram for DirectGraphicalModels::fex::CGradient:

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Public Member Functions
	CGradient (const Mat &img)
	Constructor. More...
virtual	~CGradient (void)
virtual Mat	get (void) const
	Extracts and returns the required feature. More...
Public Member Functions inherited from DirectGraphicalModels::fex::ILocalFeatureExtractor
	ILocalFeatureExtractor (const Mat &img)
	Constructor. More...
virtual	~ILocalFeatureExtractor (void)
Public Member Functions inherited from DirectGraphicalModels::fex::IFeatureExtractor
	IFeatureExtractor (const Mat &img)
	Constructor. More...
virtual	~IFeatureExtractor (void)

Static Public Member Functions
static Mat	get (const Mat &img, float mid=GRADIENT_MAX_VALUE)
	Extracts the gradient feature. More...

Static Protected Member Functions
static Mat	getDerivativeX (const Mat &img)
static Mat	getDerivativeY (const Mat &img)

Friends
class	CHOG

Additional Inherited Members
Protected Attributes inherited from DirectGraphicalModels::fex::IFeatureExtractor
const Mat	m_img
	Container for the image, from which the features are to be extracted. More...

Detailed Description

Gradient feature extraction class.

Author

Sergey G. Kosov, serge.nosp@m.y.ko.nosp@m.sov@p.nosp@m.roje.nosp@m.ct-10.nosp@m..de

Definition at line 15 of file Gradient.h.

Constructor & Destructor Documentation

CGradient()

DirectGraphicalModels::fex::CGradient::CGradient ( const Mat &  img )

inline

Constructor.

Parameters

img	Input image of type CV_8UC1 or CV_8UC3.

Definition at line 23 of file Gradient.h.

~CGradient()

virtual DirectGraphicalModels::fex::CGradient::~CGradient ( void  )

inlinevirtual

Definition at line 24 of file Gradient.h.

Member Function Documentation

get() [1/2]

virtual Mat DirectGraphicalModels::fex::CGradient::get ( void  ) const

inlinevirtual

Extracts and returns the required feature.

Returns

The feature image.

Implements DirectGraphicalModels::fex::ILocalFeatureExtractor.

Definition at line 26 of file Gradient.h.

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get() [2/2]

Mat DirectGraphicalModels::fex::CGradient::get ( const Mat &  img, float  mid = GRADIENT_MAX_VALUE  )

static

Extracts the gradient feature.

This function calculates the magnitude of gradient of the input image as follows:

\[gradient=\sqrt{\left(\frac{d\,img}{dx}\right)^2+\left(\frac{d\,img}{dy}\right)^2},\]

where \(\frac{d\,img}{dx}\) and \(\frac{d\,img}{dy}\) are the first x and y central derivatives of the input image.
As \(gradient\in[0; 255\,\sqrt{2}]\), this function performs two-linear mapping of the gradient values to the interval \([0; 255]\), such that:

\begin{eqnarray*}0&\rightarrow&0 \\ mid&\rightarrow&255 \\ 255\,\sqrt{2}&\rightarrow&255\end{eqnarray*}

For more details on mapping refer to the two_linear_mapper() function.

Parameters

img	Input image of type CV_8UC1 or CV_8UC3.
mid	Parameter for the two-linear mapping of the feature: \(mid\in(0;255\sqrt{2}]\). (Ref. two_linear_mapper()).

Returns

The gradient feature image of type CV_8UC1.

Definition at line 7 of file Gradient.cpp.

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getDerivativeX()

Mat DirectGraphicalModels::fex::CGradient::getDerivativeX ( const Mat &  img )

staticprotected

Definition at line 35 of file Gradient.cpp.

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getDerivativeY()

Mat DirectGraphicalModels::fex::CGradient::getDerivativeY ( const Mat &  img )

staticprotected

Definition at line 49 of file Gradient.cpp.

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Friends And Related Function Documentation

CHOG

friend class CHOG

friend

Definition at line 17 of file Gradient.h.

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The documentation for this class was generated from the following files:

• D:/Projects/DGM/modules/FEX/Gradient.h
• D:/Projects/DGM/modules/FEX/Gradient.cpp