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

Class MTBSnakeEnergyCDIB_Gradient

java.lang.Object

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

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

All Implemented Interfaces:

MTBActiveContourEnergy, MTBActiveContourEnergyDerivable, MTBSnakeEnergyComputable, MTBSnakeEnergyDerivable

@ALDDerivedClass
 @ALDParametrizedClass
public class MTBSnakeEnergyCDIB_Gradient
extends MTBSnakeEnergyCDImageBased

External snake energy based on local intensity gradients.

The energy for a snake C is defined as follows:

\begin{equation*} E(C) = \int_0^1 - | \nabla I(C(s)) |^2 ds \end{equation*}

Applying this energy a snake tends to move towards image locations with large gradient magnitudes.

Author:

Danny Misiak

See Also:

GradientFieldCalculator2D

Field Summary

Fields

Modifier and Type	Field and Description
private MTBVectorField2D	gradField
private MTBImage	image The given input image to calculate the external energy from it.
private MTBImageDouble	imageNormalized Normalized version of input image used in calculations.

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_Gradient() Constructor to create a new SnakeExternalEnergyGradient object.
MTBSnakeEnergyCDIB_Gradient(MTBImage img) Constructor to create a new SnakeExternalEnergyGradient object.

Method Summary

Modifier and Type	Method and Description
Jama.Matrix	getDerivative_VectorPart(SnakeOptimizerSingleVarCalc opt) Returns the vector part of this energy for snake optimization.
double	getDerivativeX(double x, double y) Get x-derivative of negative absolute gradient value to the power of two (external energy) at given position using central differences.
double	getDerivativeY(double x, double y) Get y-derivative of negative absolute gradient value to the power of two (external energy) at given position using central differences.
double	getValue(double x, double y) Returns the negative absolute gradient value to the power of 2 (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() Normalize the external energy in a range [-1.0, 1.0].
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, 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

The given input image to calculate the external energy from it.

imageNormalized

private MTBImageDouble imageNormalized

Normalized version of input image used in calculations.

gradField

private MTBVectorField2D gradField

Constructor Detail

MTBSnakeEnergyCDIB_Gradient

public MTBSnakeEnergyCDIB_Gradient()

Constructor to create a new SnakeExternalEnergyGradient object.

Parameters:

img - input image

Throws:

de.unihalle.informatik.Alida.exceptions.ALDOperatorException

de.unihalle.informatik.Alida.exceptions.ALDProcessingDAGException

MTBSnakeEnergyCDIB_Gradient

public MTBSnakeEnergyCDIB_Gradient(MTBImage img)

Constructor to create a new SnakeExternalEnergyGradient object.

Parameters:

img - input image

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.

getValue

public double getValue(double x,
                       double y)

Returns the negative absolute gradient value to the power of 2 (the external energy) at the given position.

Specified by:

getValue in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of position

y - y-coordinate of position

Returns:

Absolute value of external energy.

getDerivative_VectorPart

public Jama.Matrix getDerivative_VectorPart(SnakeOptimizerSingleVarCalc opt)

Description copied from interface: MTBSnakeEnergyDerivable

Returns the vector part of this energy for snake optimization.

Specified by:

getDerivative_VectorPart in interface MTBSnakeEnergyDerivable

Overrides:

getDerivative_VectorPart in class MTBSnakeEnergyCDImageBased

Parameters:

opt - Calling snake optimizer.

Returns:

Optimization vector for this energy object.

getDerivativeX

public double getDerivativeX(double x,
                             double y)

Get x-derivative of negative absolute gradient value to the power of two (external energy) at given position using central differences.

Specified by:

getDerivativeX in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of pixel position

y - y-coordinate of pixel position

Returns:

x-derivative value at given position.

getDerivativeY

public double getDerivativeY(double x,
                             double y)

Get y-derivative of negative absolute gradient value to the power of two (external energy) at given position using central differences.

Specified by:

getDerivativeY in class MTBSnakeEnergyCDImageBased

Parameters:

x - x-coordinate of pixel position

y - y-coordinate of pixel position

Returns:

y-derivative value at given position.

normalizeEnergy

public void normalizeEnergy()

Description copied from class: MTBSnakeEnergyCDImageBased

Normalize the external energy in a range [-1.0, 1.0]. The user implements how the energy is normalized. The range can also be [0.0, 1.0] or something else, but the range must be inside [-1.0, 1.0]. The normalization is called in the initEnergy method of the energy.

Specified by:

normalizeEnergy in class MTBSnakeEnergyCDImageBased

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.