de.unihalle.informatik.MiToBo.segmentation.snakes.energies

Class MTBSnakeEnergyCDIB_GVF2D

java.lang.Object

de.unihalle.informatik.MiToBo.segmentation.snakes.energies.MTBSnakeEnergyCDImageBased

de.unihalle.informatik.MiToBo.segmentation.snakes.energies.MTBSnakeEnergyCDIB_GVF2D

All Implemented Interfaces:

MTBActiveContourEnergy, MTBActiveContourEnergyDerivable, MTBSnakeEnergyComputable, MTBSnakeEnergyDerivable

@ALDDerivedClass
 @ALDParametrizedClass
public class MTBSnakeEnergyCDIB_GVF2D
extends MTBSnakeEnergyCDImageBased

Class for external energy of a GVF field energy vector. The GVF field from a given image returns to energy flow (vector for x- and y-direction). Every energy vector is stored in a one dimensional array, so the width of the image is used to get a energy value at position (x,y). The GVF field can be normalized in the range[-1,1], see `normalizeEnergy` method.

Author:

Danny Misiak

See Also:

GVFFieldCalculator2D

Field Summary

Fields

Modifier and Type	Field and Description
private double[]	energyPotential Potential field reconstructed from GVF.
(package private) MTBVectorField2D	gvf The resulting gradient vector flow field.
private MTBImage	image
private int	numIterations

Fields inherited from class de.unihalle.informatik.MiToBo.segmentation.snakes.energies.MTBSnakeEnergyCDImageBased

height, normalizationFactor, normMode, scaleFactor, width

Fields inherited from interface de.unihalle.informatik.MiToBo.segmentation.snakes.energies.MTBSnakeEnergyDerivable

targetEnergyRange

Constructor Summary

Constructors

Constructor and Description
MTBSnakeEnergyCDIB_GVF2D() Default constructor.
MTBSnakeEnergyCDIB_GVF2D(MTBImage _image, int _numIterations) Constructor to create a new SnakeExternalEnergyGVF2D object.

Method Summary

Modifier and Type	Method and Description
double	getDerivativeX(double x, double y) Get x-derivative of external snake energy at given position.
double	getDerivativeY(double x, double y) Get y-derivative of external snake energy at given position.
MTBVectorField2D	getGVF() Get the calculated Gradient Vector Flow field.
double[]	getPotential() Get the energy potential field from this external energy.
double	getValue(double x, double y) Returns the value of the external energy at the given position.
boolean	initEnergy(SnakeOptimizerSingle o) Init routine which is called once before the energy is actually used.
void	normalizeEnergy() Normalization of the GVF field. !!!
void	saveExtEnergy(String file) Save the gvf field in a MATLAB like file.
String	toString() Get an identifier string for the energy object.

Methods inherited from class de.unihalle.informatik.MiToBo.segmentation.snakes.energies.MTBSnakeEnergyCDImageBased

calcEnergy, calcEnergy, getDerivative_MatrixPart, getDerivative_VectorPart, getDerivativeX_norm, getDerivativeY_norm, getScaleFactor, getValue_norm, requiresCounterClockwiseContourSorting, requiresOverlapMask, setScaleFactor, updateStatus

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

image

@ALDClassParameter(label="Input Image")
private MTBImage image

numIterations

@ALDClassParameter(label="Number of Iterations")
private int numIterations

gvf

MTBVectorField2D gvf

The resulting gradient vector flow field.

energyPotential

private double[] energyPotential

Potential field reconstructed from GVF.

Constructor Detail

MTBSnakeEnergyCDIB_GVF2D

public MTBSnakeEnergyCDIB_GVF2D()

Default constructor.

MTBSnakeEnergyCDIB_GVF2D

public MTBSnakeEnergyCDIB_GVF2D(MTBImage _image,
                                int _numIterations)

Constructor to create a new SnakeExternalEnergyGVF2D object.

Parameters:

image - input image for calculating the gvf field

numIterations - number of iterations used for calculating the gvf field

Method Detail

initEnergy

public boolean initEnergy(SnakeOptimizerSingle o)

Description copied from interface: MTBSnakeEnergyDerivable

Init routine which is called once before the energy is actually used.

In this routine global parameter settings can be handled or other initialization stuff be done. The SnakeOptimizer will call this routine once before the actual use of the energy. If no stuff needs to be done in advance the routine should at least return true.

Specified by:

initEnergy in interface MTBSnakeEnergyComputable

Specified by:

initEnergy in interface MTBSnakeEnergyDerivable

Overrides:

initEnergy in class MTBSnakeEnergyCDImageBased

Parameters:

o - Calling snake optimizer.

Returns:

True if init was successful, otherwise false.

getGVF

public MTBVectorField2D getGVF()

Get the calculated Gradient Vector Flow field.

Returns:

The GVF field as VectorField2D object.

getPotential

public double[] getPotential()

Get the energy potential field from this external energy.

Returns:

Potential field in a double array.

getValue

public double getValue(double x,
                       double y)

Returns the value of the external energy at the given position.

In case of GVFs the external energy is given by a potential field reconstructed from the given GVF. Since the potential reconstruction yields only approximate results, the energy values should be interpreted as a more or less good approximation to the real potential.

The potential is normalized so that the minimum equals 0.

Specified by:

getValue in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of position.

y - y-coordinate of position.

Returns:

Absolute value of external energy (always positive!).

getDerivativeX

public double getDerivativeX(double x,
                             double y)

Get x-derivative of external snake energy at given position.

Specified by:

getDerivativeX in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of pixel position

y - y-coordinate of pixel position

Returns:

Negative x-derivative value at given position.

getDerivativeY

public double getDerivativeY(double x,
                             double y)

Get y-derivative of external snake energy at given position.

Specified by:

getDerivativeY in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of pixel position

y - y-coordinate of pixel position

Returns:

Negative y-derivative value at given position.

saveExtEnergy

public void saveExtEnergy(String file)

Save the gvf field in a MATLAB like file.

Parameters:

file - complete path to the file which should be saved

normalizeEnergy

public void normalizeEnergy()

 
 Normalization of the GVF field.
 
 !!! ATTENTION: the GVF field is normalized in range [-1.0, 1.0] !!!
                Independent of the given lower or upper bound values,
                because the gradient can be negative.
 

Specified by:

normalizeEnergy in class MTBSnakeEnergyCDImageBased

Throws:

de.unihalle.informatik.Alida.exceptions.ALDOperatorException

de.unihalle.informatik.Alida.exceptions.ALDOperatorException

toString

public String toString()

Description copied from interface: MTBSnakeEnergyDerivable

Get an identifier string for the energy object.

When meta parameters are saved to a file, configuration objects need to be converted to strings. Consequently, each snake energy should be associated with a unique and descriptive string for later reference.

Specified by:

toString in interface MTBSnakeEnergyComputable

Specified by:

toString in interface MTBSnakeEnergyDerivable

Overrides:

toString in class Object

Returns:

Identifier string.