lti::regionShapeFeatures Class Reference

This functor computes descriptors for shapes, decomposing a binary mask as a sum of some basis functions. More...

#include <ltiRegionShapeFeatures.h>

Inheritance diagram for lti::regionShapeFeatures:

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Collaboration diagram for lti::regionShapeFeatures:

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List of all members.

Classes
class	parameters
	the parameters for the class regionShapeFeatures More...
Public Member Functions
	regionShapeFeatures ()
	regionShapeFeatures (const parameters &par)
	regionShapeFeatures (const regionShapeFeatures &other)
virtual	~regionShapeFeatures ()
virtual const char *	getTypeName () const
bool	apply (const channel8 &src, channel &dest) const
bool	apply (const channel8 &src, dvector &dest) const
bool	apply (const channel8 &src, channel &dest1, channel &dest2) const
bool	apply (const channel8 &src, dvector &dest1, dvector &dest2) const
bool	reconstruct (const channel &coef1, const channel &coef2, channel &shape1, channel &shape2) const
bool	getBasisFunction (const int n, const int m, channel &real, channel &imag) const
regionShapeFeatures &	copy (const regionShapeFeatures &other)
regionShapeFeatures &	operator= (const regionShapeFeatures &other)
virtual functor *	clone () const
virtual bool	updateParameters ()
const parameters &	getParameters () const
Protected Member Functions
void	dot (const channel &reA, const channel &imA, const channel &reB, const channel &imB, float &real, float &imag) const
bool	calcLUT ()
bool	testOrthogonality (channel &ortho) const
void	resizeMask (const channel8 &src, channel &ssrc) const
double	fac (int arg)
Static Protected Member Functions
static float	binarize (const float &x)
Protected Attributes
std::vector< std::vector < channel > >	lutR
std::vector< std::vector < channel > >	lutI
channel	radLut
parameters::basisFunctionsType	lastBasisFunctionSet
std::vector< std::vector< bool > >	vecNM

Detailed Description

This functor computes descriptors for shapes, decomposing a binary mask as a sum of some basis functions.

Several basis function sets have been implemented:

MPEG-7: the region shape descriptor of MPEG-7 uses the ART transformation, which projects the shape into the set $V_{nm}(\rho,\theta)$ of non-orthogonal basis functions, defined as $V_{nm}(\rho,\theta) = A_m(\theta) R_n(\rho)$ , where
$A_m(\theta) = \frac{1}{2\pi} \exp(jm\theta)$

$R_n(\rho) = \begin{cases} 1 & n=0\\ 2\cos(\pi n \rho) & n \neq 0 \end{cases}$
More information about this descriptor can be found in Miroslaw Bober, "MPEG-7 Visual Shape Descriptors", IEEE Transactions on Circuits and Systems for Video Technology, Vol. 11, No. 6, June 2001. or http://www.ctr.columbia.edu/~sfchang/course/vis/REF/bober-01.pdf

Radial Orthogonal Basis Functions: Similar to the MPEG-7 descriptors, but with an orthogonal radial component:
$R_n(\rho) = \begin{cases} 1 & n=0\\ 2\cos(2\pi n \rho) & n \neq 0 \end{cases}$

Zernike Moments: The theory about them can be found: A. Khotanzad and Y.H. Hong. "Invariant Image Recognition by Zernike Moments". IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol. 12, No. 5, May 1990, pp. 489-497

Tschebichef Moments need still to be implemented.

Constructor & Destructor Documentation

lti::regionShapeFeatures::regionShapeFeatures ( )

default constructor

lti::regionShapeFeatures::regionShapeFeatures ( const parameters & par )

default constructor with parameters

lti::regionShapeFeatures::regionShapeFeatures ( const regionShapeFeatures & other )

copy constructor

Parameters:

other

the object to be copied

virtual lti::regionShapeFeatures::~regionShapeFeatures ( ) [virtual]

destructor

Member Function Documentation

bool lti::regionShapeFeatures::apply	(	const channel8 &	src,
		dvector &	dest1,
		dvector &	dest2
	)			const

operates on the given parameter.

Parameters:

	src	channel8 with the input binary mask. All not-object pixels must be zero. The object pixels must have a value 255.
	dest1	feature vector with real part or magnitude of the coefficients, depending on the value of parameters::polar.
	dest2	feature vector with imaginary part or phase of the coefficients, depending on the value of parameters::polar.

Returns:: true if apply successful or false otherwise.

bool lti::regionShapeFeatures::apply	(	const channel8 &	src,
		channel &	dest1,
		channel &	dest2
	)			const

operates on the given parameter.

Parameters:

	src	channel8 with the input binary mask. All not-object pixels must be zero. The object pixels must have a value 255.
	dest1	channel with real part or magnitude of the coefficients, depending on the value of parameters::polar.
	dest2	channel with imaginary part or phase of the coefficients, depending on the value of parameters::polar.

Returns:: true if apply successful or false otherwise.

bool lti::regionShapeFeatures::apply	(	const channel8 &	src,
		dvector &	dest
	)			const `[virtual]`

operates on the given parameter.

Parameters:

	src	channel8 with the input binary mask. All not-object pixels must be zero. The object pixels must have a value 255.
	dest	feature vector with coefficients for the base functions. (real part or magnitude, depending on parameters::polar value)

Returns:: true if apply successful or false otherwise.

Reimplemented from lti::globalFeatureExtractor.

bool lti::regionShapeFeatures::apply	(	const channel8 &	src,
		channel &	dest
	)			const

operates on the given parameter.

Parameters:

	src	channel8 with the input binary mask. All not-object pixels must be zero. The object pixels must have a value 255.
	dest	channel with coefficients for the base functions. (real part or magnitude, depending on parameters::polar value)

Returns:: true if apply successful or false otherwise.

static float lti::regionShapeFeatures::binarize ( const float & x ) [static, protected]

static function used to binarize a channel.

All values under 0.5 will be set to 0 and all values above 0.5 will be set to 1.0

bool lti::regionShapeFeatures::calcLUT ( ) [protected]

calculates the look up tables (LUT) for the transformation (suitable to the given parameters::maskSize)

Returns:: true if successful

virtual functor* lti::regionShapeFeatures::clone ( ) const [virtual]

returns a pointer to a clone of this functor.

Reimplemented from lti::globalFeatureExtractor.

regionShapeFeatures& lti::regionShapeFeatures::copy ( const regionShapeFeatures & other )

copy data of "other" functor.

Parameters:

other

the functor to be copied

Returns:: a reference to this functor object

Reimplemented from lti::globalFeatureExtractor.

void lti::regionShapeFeatures::dot	(	const channel &	reA,
		const channel &	imA,
		const channel &	reB,
		const channel &	imB,
		float &	real,
		float &	imag
	)			const `[protected]`

dot product between two matrices of the same size

double lti::regionShapeFeatures::fac ( int arg ) [protected]

compute factorial of arg

bool lti::regionShapeFeatures::getBasisFunction	(	const int	n,
		const int	m,
		channel &	real,
		channel &	imag
	)			const

get one of the basis functions currently being used.

The indices must be in the valid range (specified in the parameters), otherwise the function will return false.

Parameters:

	n	radial component (row)
	m	angular component (column)
	real	real part of the basis function
	imag	imaginary part of the basis function

Returns:: true if successful, false otherwise

const parameters& lti::regionShapeFeatures::getParameters ( ) const

returns used parameters

Reimplemented from lti::globalFeatureExtractor.

virtual const char* lti::regionShapeFeatures::getTypeName ( ) const [virtual]

returns the name of this type ("regionShapeFeatures")

Reimplemented from lti::globalFeatureExtractor.

regionShapeFeatures& lti::regionShapeFeatures::operator= ( const regionShapeFeatures & other )

alias for copy member

Parameters:

other

the functor to be copied

Returns:: a reference to this functor object

Reimplemented from lti::functor.

bool lti::regionShapeFeatures::reconstruct	(	const channel &	coef1,
		const channel &	coef2,
		channel &	shape1,
		channel &	shape2
	)			const

This method is for debugging purposes only.

It provides a tentative reconstruction algorithm for the original shape using the given coefficients. Depending on the parameters::polar the output will be in cartesic or in polar form.

Parameters:

	coef1	real part (or magnitude) of the coefficients.
	coef2	imaginary part (or phase) of the coefficients.
	shape1	reconstructed real part (or magnitude)
	shape2	reconstructed imaginary part (or phase)

Returns:: true if successful, false otherwise.

void lti::regionShapeFeatures::resizeMask	(	const channel8 &	src,
		channel &	ssrc
	)			const `[protected]`

crop the object in the mask and resizes it to the parameters::maskSize (here: the center of mass of the object is in the center of the new image)

bool lti::regionShapeFeatures::testOrthogonality ( channel & ortho ) const [protected]

Test the orthogonality of the base functions The comparition matrix will be a square matrix with the size.x*sizey elements at one size.

virtual bool lti::regionShapeFeatures::updateParameters ( ) [virtual]

set functor's parameters.

This member makes a copy of theParam: the functor will keep its own copy of the parameters!

Returns:: true if successful, false otherwise

Reimplemented from lti::functor.

Member Data Documentation

parameters::basisFunctionsType lti::regionShapeFeatures::lastBasisFunctionSet [protected]

flag to remember the last basis function set

std::vector< std::vector<channel> > lti::regionShapeFeatures::lutI [protected]

imaginary part of the basis functions (LUT)

std::vector< std::vector<channel> > lti::regionShapeFeatures::lutR [protected]

real part of the basis functions (LUT)

channel lti::regionShapeFeatures::radLut [protected]

radius matrix.

It will contain the distance of a pixel to the center of the image: f(x,y) = radius ; radius = ((x-xcenter)^2+(y-ycenter)^2)^0.5

std::vector<std::vector<bool> > lti::regionShapeFeatures::vecNM [protected]

used to decide whether zernike moment (n,m) exists

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

ltiRegionShapeFeatures.h

lti::regionShapeFeatures Class Reference

Classes

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation