Common class, which unites feature extraction algorithms. More...

#include <CommonFeatureExtractor.h>

Inheritance diagram for DirectGraphicalModels::fex::CCommonFeatureExtractor:

Collaboration diagram for DirectGraphicalModels::fex::CCommonFeatureExtractor:

Public Member Functions
	CCommonFeatureExtractor (const Mat &img)
	Constructor. More...

virtual	~CCommonFeatureExtractor (void)

virtual Mat	get (void) const
	Returns the input image. More...

CGlobalFeatureExtractor	toGlobal (void) const
	Allows for global-features extraction. More...

CCommonFeatureExtractor	getCoordinate (coordinateType type=COORDINATE_ORDINATE) const
	Extracts a coordinate feature. More...

CCommonFeatureExtractor	getIntensity (cv::Scalar weight=CV_RGB(0.333, 0.333, 0.333)) const
	Extracts the intesity feature. More...

CCommonFeatureExtractor	getHSV (void) const
	Extracts the HSV feature. More...

CCommonFeatureExtractor	getHue (void) const
	Extracts the hue feature. More...

CCommonFeatureExtractor	getSaturation (void) const
	Extracts the saturation feature. More...

CCommonFeatureExtractor	getBrightness (void) const
	Extracts the brightness feature. More...

CCommonFeatureExtractor	getGradient (float mid=GRADIENT_MAX_VALUE) const
	Extracts the gradient feature. More...

CCommonFeatureExtractor	getNDVI (byte midPoint=127) const
	Extracts the NDVI (normalized difference vegetation index) feature. More...

CCommonFeatureExtractor	getDistance (byte threshold=16, double multiplier=4.0) const
	Extracts the distance feature. More...

CCommonFeatureExtractor	getHOG (int nBins=9, SqNeighbourhood nbhd=sqNeighbourhood(5)) const
	Extracts the HOG (<a href="http://en.wikipedia.org/wiki/Histogram_of_oriented_gradients"target="_blank">histogram of oriented gradients) feature. More...

CCommonFeatureExtractor	getSIFT () const
	Extracts the SIFT (scale-invariant feature transform) feature. More...

CCommonFeatureExtractor	getVariance (SqNeighbourhood nbhd=sqNeighbourhood(5)) const
	Extracts the variance feature. More...

CCommonFeatureExtractor	getSparseCoding (const Mat &D, SqNeighbourhood nbhd=sqNeighbourhood(3)) const
	Extracts the sparse coding feature. More...

CCommonFeatureExtractor	reScale (SqNeighbourhood nbhd=sqNeighbourhood(5)) const
	Extracts the scale feature. More...

CCommonFeatureExtractor	invert (void) const
	Inverts the source image. More...

CCommonFeatureExtractor	blur (int R=2) const
	Performs Gaussian blurring of the source image. More...

CCommonFeatureExtractor	autoContrast (void) const
	Performs histogram stretching of the source image. More...

CCommonFeatureExtractor	thresholding (byte threshold) const
	Performs thresholding on the source image. More...

CCommonFeatureExtractor	getChannel (int channel) const
	Extracts one channel from the source image. 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)

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

Common class, which unites feature extraction algorithms.

In order to simplify the user feature extraction code, this class provides fluent interface. Please see the example code below for more details.

CCommonFeatureExtractor fex(img);
Mat    saturation = fex.getSaturation().invert().get();                   // Inverted saturation feature
Mat    variance   = fex.getGradient().getVariance().blur().get();         // Varience of the gradient feature, after Gaussian blur
Mat    intesity   = fex.getIntensity().reScale(sqNeighbourhood(2)).get(); // Intencity feature, calculated at scale of window size 5 x 5 pixels
size_t nLines     = fex.autoContrast().toGlobal().getNumLines();          // Global-feature: quantity of straight lines in image

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 52 of file CommonFeatureExtractor.h.

Constructor & Destructor Documentation

◆ CCommonFeatureExtractor()

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

inline

Constructor.

Parameters

img	Input image.

Definition at line 59 of file CommonFeatureExtractor.h.

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◆ ~CCommonFeatureExtractor()

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

inlinevirtual

Definition at line 60 of file CommonFeatureExtractor.h.

Member Function Documentation

◆ autoContrast()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::autoContrast ( void ) const

Performs histogram stretching of the source image.

Returns: Common feature extractor class with with contrast-enhanced feature with the same number of channels.

Definition at line 20 of file CommonFeatureExtractor.cpp.

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◆ blur()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::blur ( int R = 2 ) const

Performs Gaussian blurring of the source image.

Parameters

R	Radius of the Gaussian filter box: \((2R+1)\times(2R+1)\).

Returns: Common feature extractor class with blurred feature with the same number of channels.

Definition at line 12 of file CommonFeatureExtractor.cpp.

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◆ get()

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

inlinevirtual

Returns the input image.

Returns: The input image.

Implements DirectGraphicalModels::fex::ILocalFeatureExtractor.

Definition at line 66 of file CommonFeatureExtractor.h.

◆ getBrightness()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getBrightness ( void ) const

inline

Extracts the brightness feature.

This function represents the input image in HSV (hue-saturation-value) color model and returns the value channel.

Returns: Common feature extractor class with extracted brightness feature of type CV_8UC1.

Definition at line 110 of file CommonFeatureExtractor.h.

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◆ getChannel()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getChannel ( int channel ) const

Extracts one channel from the source image.

Parameters

channel Index of the required channel.

Returns: Common feature extractor class with the required channel as a feature.

Definition at line 59 of file CommonFeatureExtractor.cpp.

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◆ getCoordinate()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getCoordinate ( coordinateType type = COORDINATE_ORDINATE ) const

inline

Extracts a coordinate feature.

This function calculates the coordinate feature of image pixels, based inly on theirs coordinates.

Parameters

type	Type of the coordinate feature (Ref. coordinateType).

Returns: Common feature extractor class with extracted coordinate feature of type CV_8UC1.

Definition at line 79 of file CommonFeatureExtractor.h.

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◆ getDistance()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getDistance	(	byte	threshold = `16`,
		double	multiplier = `4.0`
	)		const

inline

Extracts the distance feature.

For each pixel of the source image this function calculates the distance to the closest pixel, which value is larger or equal to threshold. Resulting feature image is multiplied by multiplier

Parameters

threshold	Threshold value.
multiplier	Amplification coefficient for the resulting feature image.

Returns: Common feature extractor class with extracted distance feature of type CV_8UC1.

Definition at line 147 of file CommonFeatureExtractor.h.

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◆ getGradient()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getGradient ( float mid = GRADIENT_MAX_VALUE ) const

inline

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

mid	Parameter for the two-linear mapping of the feature: \(mid\in(0;255\sqrt{2}]\). (Ref. two_linear_mapper()).

Returns: Common feature extractor class with extracted gradient feature of type CV_8UC1.

Definition at line 121 of file CommonFeatureExtractor.h.

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◆ getHOG()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getHOG	(	int	nBins = `9`,
		SqNeighbourhood	nbhd = `sqNeighbourhood(5)`
	)		const

inline

Extracts the HOG (<a href="http://en.wikipedia.org/wiki/Histogram_of_oriented_gradients"target="_blank">histogram of oriented gradients) feature.

For each pixel of the source image this function calculates the histogram of oriented gradients inside the pixel's neighbourhood nbhd. The histogram consists of nBins values, it is normalized, and stored as nBins channel image, thus, the channel index corresponds to the histogram index.

Parameters

nBins	Number of bins. Hence a single bin covers an angle of \(\frac{180^\circ}{nBins}\).
nbhd	Neighborhood around the pixel, where its histogram is estimated. (Ref. SqNeighbourhood).

Returns: Common feature extractor class with extracted HOG feature of type CV_8UC{n}, where \(n=nBins\).

Definition at line 156 of file CommonFeatureExtractor.h.

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◆ getHSV()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getHSV ( void ) const

inline

Extracts the HSV feature.

This function transforms the input image into HSV (hue-saturation-value) color space.

Returns: The (hue-saturation-value) feature image of type CV_8UC3.

Definition at line 92 of file CommonFeatureExtractor.h.

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◆ getHue()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getHue ( void ) const

inline

Extracts the hue feature.

This function represents the input image in HSV (hue-saturation-value) color model and returns the hue channel.

Returns: Common feature extractor class with extracted hue feature of type CV_8UC1.

Definition at line 98 of file CommonFeatureExtractor.h.

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◆ getIntensity()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getIntensity ( cv::Scalar weight = CV_RGB(0.333, 0.333, 0.333) ) const

inline

Extracts the intesity feature.

This function calculates the intesity of the input image as follows:

\[ intensity=weight_0\cdot img.RED+weight_1\cdot img.GREEN+weight_2\cdot img.BLUE \]

Parameters

weight The weight coefficients, which determine the contribution of each color channel to the resulting intensity.

Returns: Common feature extractor class with extracted intensity feature of type CV_8UC1.

Definition at line 86 of file CommonFeatureExtractor.h.

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◆ getNDVI()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getNDVI ( byte midPoint = 127 ) const

inline

Extracts the NDVI (normalized difference vegetation index) feature.

This function calculates the NDVI from the input image as follows:

\[ NDVI=\frac{NIR-VIS}{NIR+VIS},\]

where \(NIR\) designates the near-infra-red data, and \(VIS\) - visible data. The algorithm assumes that the near-infra-red data is stored in the red image channel and the visible data - in the remaining two channels:

\begin{eqnarray*}NIR&=&img.RED \\ VIS&=&\frac{1}{2}\,img.GREEN+\frac{1}{2}\,img.BLUE.\end{eqnarray*}

As \(NDVI\in[-1; 1]\), this function performs two-linear mapping of the NDVI values to the interval \([0; 255]\), such that:

\begin{eqnarray*}-1&\rightarrow&0 \\ 0&\rightarrow&midPoint \\ 1&\rightarrow&255\end{eqnarray*}

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

Parameters

midPoint

Parameter for the two-linear mapping of the feature (Ref. two_linear_mapper()).

Common values are:

0 - cut off the negative NDVI values;

127 - linear mapping;

255 - cut off the positive NDVI values.

Returns: Common feature extractor class with extracted NDVI feature of type CV_8UC1.

Definition at line 138 of file CommonFeatureExtractor.h.

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◆ getSaturation()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getSaturation ( void ) const

inline

Extracts the saturation feature.

This function represents the input image in HSV (hue-saturation-value) color model and returns the saturation channel.

Returns: Common feature extractor class with extracted saturation feature of type CV_8UC1.

Definition at line 104 of file CommonFeatureExtractor.h.

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◆ getSIFT()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getSIFT ( ) const

inline

Extracts the SIFT (scale-invariant feature transform) feature.

For each pixel of the source image this function performs the scale-invariant feature transform.

Returns: Common feature extractor class with extracted SIFT feature of type CV_8UC{128}.

Definition at line 162 of file CommonFeatureExtractor.h.

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◆ getSparseCoding()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getSparseCoding	(	const Mat &	D,
		SqNeighbourhood	nbhd = `sqNeighbourhood(3)`
	)		const

inline

Extracts the sparse coding feature.

For each pixel of the source image this function calculates the sparse coding feature within the pixel's neighbourhood nbhd.

This fuction supports dictionaries with nWords less or equal to 512 words. For larger dictionaries use CSparseCoding::get_v() function directly.

Parameters

D	Sparse dictionary \(D\): Mat(size nWords x blockSize^2; type CV_32FC1). Dictionary should be learned from a training data with CSparseDictionary::train() function, or it may be loaded directed from a dic file with CSparseDictionary::getDictionary("dictionary.dic").
nbhd	Neighborhood around the pixel, where the feature is estimated. (Ref. SqNeighbourhood).

Returns: Common feature extractor class with extracted sparse coding feature of type CV_8UC{nWords}.

Definition at line 180 of file CommonFeatureExtractor.h.

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◆ getVariance()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::getVariance ( SqNeighbourhood nbhd = sqNeighbourhood(5) ) const

inline

Extracts the variance feature.

For each pixel of the source image this function calculates the variance within the pixel's neighbourhood nbhd.

Parameters

nbhd	Neighborhood around the pixel, where the variance is estimated. (Ref. SqNeighbourhood).

Returns: Common feature extractor class with extracted variance feature of type CV_8UC1.

Definition at line 169 of file CommonFeatureExtractor.h.

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◆ invert()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::invert ( void ) const

Inverts the source image.

Returns: Common feature extractor class with the inverted feature with the same number of channels.

Definition at line 5 of file CommonFeatureExtractor.cpp.

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◆ reScale()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::reScale ( SqNeighbourhood nbhd = sqNeighbourhood(5) ) const

inline

Extracts the scale feature.

For each pixel of the source image this function calculates the mean value within the pixel's neighbourhood nbhd. Using different neighbourhood radii, it alows for different scale representations of the nput features.

Parameters

nbhd	Neighborhood around the pixel, where the mean is estimated. (Ref. SqNeighbourhood).

Returns: Common feature extractor class with extracted scale feature of type CV_8UC1.

Definition at line 188 of file CommonFeatureExtractor.h.

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◆ thresholding()

CCommonFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::thresholding ( byte threshold ) const

Performs thresholding on the source image.

\[ res_i = \left\{\begin{array}{ll} 255 & \text{if}~~res_i > threshold \\ 0 & \text{otherwise} \end{array} \right. \]

Returns: A binary image of type CV_8UC1 with values {0, 255 }

Definition at line 43 of file CommonFeatureExtractor.cpp.

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◆ toGlobal()

CGlobalFeatureExtractor DirectGraphicalModels::fex::CCommonFeatureExtractor::toGlobal ( void ) const

inline

Allows for global-features extraction.

Returns: The base global feature extractor class

Definition at line 72 of file CommonFeatureExtractor.h.

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

D:/Projects/DGM/modules/FEX/CommonFeatureExtractor.h
D:/Projects/DGM/modules/FEX/CommonFeatureExtractor.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ CCommonFeatureExtractor()

◆ ~CCommonFeatureExtractor()

Member Function Documentation

◆ autoContrast()

◆ blur()

◆ get()

◆ getBrightness()

◆ getChannel()

◆ getCoordinate()

◆ getDistance()

◆ getGradient()

◆ getHOG()

◆ getHSV()

◆ getHue()

◆ getIntensity()

◆ getNDVI()

◆ getSaturation()

◆ getSIFT()

◆ getSparseCoding()

◆ getVariance()

◆ invert()

◆ reScale()

◆ thresholding()

◆ toGlobal()