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

Class MTBSnakeEnergyCD_KassCurvature

java.lang.Object

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

All Implemented Interfaces:

MTBActiveContourEnergy, MTBActiveContourEnergyDerivable, MTBSnakeEnergyComputable, MTBSnakeEnergyDerivable

@ALDDerivedClass
 @ALDParametrizedClass
public class MTBSnakeEnergyCD_KassCurvature
extends Object
implements MTBSnakeEnergyDerivable, MTBSnakeEnergyComputable

Curvature energy of the pioneering paper of Kass et al.

The energy is based on second order derivatives of a snake C and is defined as follows:

\begin{equation*} E(C) = 0.5 \cdot \int_0^1 \beta(s) \cdot |C_{ss}(s)|^2 ds \end{equation*}

Note that in contrast to the original work this implementation allows for more flexible weighting parameters beta, i.e. the weighting factors may be set for each snake point individually.

In addition, the weighting parameters can dynamically be adjusted by providing the energy with an update object, see MTBSnakeEnergyCD_KassCurvature_ParamAdapt.

Paper: Kass, Witkin and Terzopoulos, Snakes: Active Contour Models, International Journal of Computer Vision, pp. 321-331, 1988.

Author:

moeller

Field Summary

Fields

Modifier and Type	Field and Description
private double	betaInitial Weighting factor for the curvature term, should always be > 0.
private double[]	betas Vector of point-specific beta values.
private Double	maxBeta Maximal possible value of beta.
private double	normalizationFactor Normalization factor for scaling matrix entries.
private SnakeOptimizerSingle.EnergyNormalizationMode	normMode Mode of normalization.
private MTBSnakeEnergyCD_KassCurvature_ParamAdapt	pUpdater Parameter update strategy.
protected double	scaleFactor Scaling factor for image coordinates.

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

targetEnergyRange

Constructor Summary

Constructors

Constructor and Description
MTBSnakeEnergyCD_KassCurvature() Default constructor.
MTBSnakeEnergyCD_KassCurvature(double _beta, MTBSnakeEnergyCD_KassCurvature_ParamAdapt _pUpd) Constructor with dynamic parameter updater.

Method Summary

Modifier and Type	Method and Description
double	calcEnergy(SnakeOptimizerSingle opt) Calculates normalized snake energy.
double	calcEnergy(SnakeOptimizerSingle opt, int pos) Calculates length term of snake energy at a certain position for the current snake.
Jama.Matrix	getDerivative_MatrixPart(SnakeOptimizerSingleVarCalc opt) Updates matrix A given weights for the internal energy term.
Jama.Matrix	getDerivative_VectorPart(SnakeOptimizerSingleVarCalc opt) Returns the vector part of this energy for snake optimization.
double	getInitBeta() Get the initial beta value.
private double	getNormalizationFactor(SnakeOptimizerSingle opt)
double	getScaleFactor() Get scaling factor.
boolean	initEnergy(SnakeOptimizerSingle o) Init routine which is called once before the energy is actually used.
boolean	requiresCounterClockwiseContourSorting() Ask energy if contour points need to sorted counter-clockwise.
boolean	requiresOverlapMask() Ask energy if an overlap mask for all snakes jointly optimized is required.
void	setScaleFactor(double s) Set the scaling factor.
String	toString() Get an identifier string for the energy object.
void	updateStatus(SnakeOptimizerSingle o) Update internal state of energy object prior to usaging it.

Methods inherited from class java.lang.Object

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

Field Detail

betaInitial

@ALDClassParameter(label="Initial Beta")
private double betaInitial

Weighting factor for the curvature term, should always be > 0.

pUpdater

@ALDClassParameter(label="Parameter Updater")
private MTBSnakeEnergyCD_KassCurvature_ParamAdapt pUpdater

Parameter update strategy.

normMode

private SnakeOptimizerSingle.EnergyNormalizationMode normMode

Mode of normalization.

normalizationFactor

private double normalizationFactor

Normalization factor for scaling matrix entries.

maxBeta

private Double maxBeta

Maximal possible value of beta.

betas

private double[] betas

Vector of point-specific beta values.

scaleFactor

protected double scaleFactor

Scaling factor for image coordinates.

The factor is used to rescale image coordinates to the range [0,1]. Default scaling factor is 1.

Constructor Detail

MTBSnakeEnergyCD_KassCurvature

public MTBSnakeEnergyCD_KassCurvature()

Default constructor.

MTBSnakeEnergyCD_KassCurvature

public MTBSnakeEnergyCD_KassCurvature(double _beta,
                                      MTBSnakeEnergyCD_KassCurvature_ParamAdapt _pUpd)

Constructor with dynamic parameter updater.

Parameters:

_beta - Weighting factor for curvature term.

_pUpd - Parameter update object.

Method Detail

setScaleFactor

public void setScaleFactor(double s)

Set the scaling factor.

Specified by:

setScaleFactor in interface MTBSnakeEnergyComputable

Specified by:

setScaleFactor in interface MTBSnakeEnergyDerivable

Parameters:

s - New scaling factor.

getScaleFactor

public double getScaleFactor()

Get scaling factor.

Specified by:

getScaleFactor in interface MTBSnakeEnergyComputable

Specified by:

getScaleFactor in interface MTBSnakeEnergyDerivable

Returns:

Scaling factor.

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

Parameters:

o - Calling snake optimizer.

Returns:

True if init was successful, otherwise false.

getInitBeta

public double getInitBeta()

Get the initial beta value.

Returns:

Intial beta.

calcEnergy

public double calcEnergy(SnakeOptimizerSingle opt)

Calculates normalized snake energy.

Specified by:

calcEnergy in interface MTBSnakeEnergyComputable

Parameters:

opt - Calling snake optimizer.

Returns:

Energy of complete snake.

calcEnergy

public double calcEnergy(SnakeOptimizerSingle opt,
                         int pos)

Calculates length term of snake energy at a certain position for the current snake.

getDerivative_MatrixPart

public Jama.Matrix getDerivative_MatrixPart(SnakeOptimizerSingleVarCalc opt)

Updates matrix A given weights for the internal energy term.

The upper left block and the lower right block of matrix A just dependent on the weight parameters alpha and beta for the internal snake energy terms.

Specified by:

getDerivative_MatrixPart in interface MTBSnakeEnergyDerivable

Parameters:

opt - Calling snake optimizer.

Returns:

Optimization matrix for this energy object.

getNormalizationFactor

private double getNormalizationFactor(SnakeOptimizerSingle opt)

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

Parameters:

opt - Calling snake optimizer.

Returns:

Optimization vector for this energy object.

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.

updateStatus

public void updateStatus(SnakeOptimizerSingle o)

Description copied from interface: MTBSnakeEnergyDerivable

Update internal state of energy object prior to usaging it.

Specified by:

updateStatus in interface MTBSnakeEnergyComputable

Specified by:

updateStatus in interface MTBSnakeEnergyDerivable

requiresCounterClockwiseContourSorting

public boolean requiresCounterClockwiseContourSorting()

Description copied from interface: MTBSnakeEnergyDerivable

Ask energy if contour points need to sorted counter-clockwise.

Specified by:

requiresCounterClockwiseContourSorting in interface MTBSnakeEnergyComputable

Specified by:

requiresCounterClockwiseContourSorting in interface MTBSnakeEnergyDerivable

Returns:

If true, counter-clockwise sorting is expected.

requiresOverlapMask

public boolean requiresOverlapMask()

Description copied from interface: MTBSnakeEnergyDerivable

Ask energy if an overlap mask for all snakes jointly optimized is required.

Specified by:

requiresOverlapMask in interface MTBSnakeEnergyComputable

Specified by:

requiresOverlapMask in interface MTBSnakeEnergyDerivable

Returns:

If true, the energy expects an overlap mask to be available.