de.unihalle.informatik.MiToBo.segmentation.levelset.core

Class DeltaApproxHelper

java.lang.Object

de.unihalle.informatik.MiToBo.segmentation.levelset.core.DeltaApproxHelper

public class DeltaApproxHelper
extends Object

Class calculating approximations to the Dirac impulse function.

The approximations used here are implemented according to

Chan and Vese, "An Active Contour Model without Edges", Scale-Space '99, LNCS 1682, pp. 141-151, Springer 1999.

Refer to DeltaApproxHelper.ApproxVersion for details about the available approximations.

Author:

Birgit Moeller

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DeltaApproxHelper.ApproxVersion Available approximations for the Heaviside function and its derivatives.

Field Summary

Fields

Modifier and Type	Field and Description
private double	epsilon Epsilon value to configure scale to use.
private DeltaApproxHelper.ApproxVersion	version Type of approximating function to use.

Constructor Summary

Constructors

Constructor and Description
DeltaApproxHelper(double eps, DeltaApproxHelper.ApproxVersion v) Default constructor.

Method Summary

Modifier and Type	Method and Description
private double	dirac_v1(double z) Implements version 1 of approximation.
private double	dirac_v2(double z) Implements version 2 of approximation.
double	getValue(double z) Calculate approximated value for given parameter value.

Methods inherited from class java.lang.Object

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

Field Detail

epsilon

private double epsilon

Epsilon value to configure scale to use.

version

private DeltaApproxHelper.ApproxVersion version

Type of approximating function to use.

Constructor Detail

DeltaApproxHelper

public DeltaApproxHelper(double eps,
                         DeltaApproxHelper.ApproxVersion v)

Default constructor.

Parameters:

eps - Value for approximation scale parameter.

v - Function version to be used for approximation.

Method Detail

getValue

public double getValue(double z)

Calculate approximated value for given parameter value.

Parameters:

z - Value for which to calculate function value.

Returns:

Calculated function value.

dirac_v1

private double dirac_v1(double z)

Implements version 1 of approximation.

Parameters:

z - Value for which to calculate function value.

Returns:

Calculated function value.

dirac_v2

private double dirac_v2(double z)

Implements version 2 of approximation.

Parameters:

z - Value for which to calculate function value.

Returns:

Calculated function value.