de.unihalle.informatik.MiToBo.segmentation.activecontours.energies

Class MTBActiveContourEnergy_CVRegionFit

java.lang.Object

de.unihalle.informatik.MiToBo.segmentation.activecontours.energies.MTBActiveContourEnergy_CVRegionFit

Direct Known Subclasses:

MTBLevelEnergyDerivable_CVRegionFit, MTBSnakeEnergyCD_CVRegionFit

public class MTBActiveContourEnergy_CVRegionFit
extends Object

Active contour energy implementing Chan-Vese region fitting for gray-scale and vector-valued, i.e. multi-channel, images.

This energy models the inner and outer regions of a single contour by a Gaussian model, i.e. each of the two regions is characterized by a mean intensity value, and deviations from this value are penalized. The energy is defined as follows:

\begin{equation*} E(C) = \int_{inside(C)} \frac{1}{N} \sum_{i=1}^N \lambda_{in,i} \cdot (I_i(x,y,z) - c_{in,i})^2 dx dy + \int_{outside(C)} \frac{1}{N} \sum_{i=1}^N \lambda_{out,i} \cdot (I_i(x,y,z) - c_{out,i})^2 dx dy \end{equation*}

Note that class 0 is interpreted as background while class 1 is taken as foreground or contour interior. If there are additional labels present in the given segmentation they are ignored.

Papers:

• Chan and Vese, Active Contours Without Edges, IEEE Transactions on Image Processing, vol. 10, no. 2, pp. 266-277, 2001.
• Chan, Sandberg and Vese, Active Contours without Edges for Vector-Valued Images, Journal of Visual Communications and Image Representation, vol. 11, pp. 130-141, 2000.

Author:

moeller

Field Summary

Fields

Modifier and Type	Field and Description
protected int[]	areas Region sizes, entry with index 0 is assumed to refer to background.
protected int	iChannels Number of channels of the image.
private CalcSegmentationStatistics	imgStatsOp Operator to calculate energy parameters, i.e., some statistical numbers on the regions of the segmentation.
protected MTBImage	inImg Image to work on.
protected double[]	lambda_in Weighting factors for inner region fit, one for each channel.
protected double[]	lambda_out Weighting factors for outer region fit, one for each channel.
protected double[][]	means Average intensities per region, first index refers to channel.

Constructor Summary

Constructors

Constructor and Description
MTBActiveContourEnergy_CVRegionFit() Default constructor.
MTBActiveContourEnergy_CVRegionFit(MTBImage im, double[] lin, double[] lout) Default constructor with arguments.

Method Summary

Modifier and Type	Method and Description
protected double	calcEnergy(MTBSegmentationInterface seg) Calculates the absolute energy value for the given segmentation.
protected double	calcInteriorEnergy(MTBSegmentationInterface seg) Calculates the interior part of energy value for the given segmentation.
protected double	getDerivative(MTBSegmentationInterface seg, int x, int y, int z) Returns the energy derivative value at position (x,y,z).
protected double	getEnergyDerivativeMaxVal() Returns the maximum possible derivative value this energy may yield.
protected double	getEnergyDerivativeMinVal() Returns the minimum possible derivative value this energy may yield.
protected double[][]	getMeans() Returns the average region intensities last calculated.
protected void	init() Method to properly initialize instances of this class.
String	toString()
protected void	updateParameters(MTBSegmentationInterface mem) Updates parameters according to given membership.

Methods inherited from class java.lang.Object

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

Field Detail

inImg

@ALDClassParameter(label="Input Image",
                   mode=ADVANCED,
                   dataIOOrder=-10)
protected transient MTBImage inImg

Image to work on.

lambda_in

@ALDClassParameter(label="Interior Lambdas per Channel",
                   mode=STANDARD,
                   dataIOOrder=-5)
protected double[] lambda_in

Weighting factors for inner region fit, one for each channel.

lambda_out

@ALDClassParameter(label="Exterior Lambdas per Channel",
                   mode=STANDARD,
                   dataIOOrder=-4)
protected double[] lambda_out

Weighting factors for outer region fit, one for each channel.

imgStatsOp

private transient CalcSegmentationStatistics imgStatsOp

Operator to calculate energy parameters, i.e., some statistical numbers on the regions of the segmentation.

areas

protected transient int[] areas

Region sizes, entry with index 0 is assumed to refer to background.

means

protected transient double[][] means

Average intensities per region, first index refers to channel.

iChannels

protected transient int iChannels

Number of channels of the image.

Constructor Detail

MTBActiveContourEnergy_CVRegionFit

public MTBActiveContourEnergy_CVRegionFit()

Default constructor.

MTBActiveContourEnergy_CVRegionFit

public MTBActiveContourEnergy_CVRegionFit(MTBImage im,
                                          double[] lin,
                                          double[] lout)

Default constructor with arguments.

Parameters:

im - Image to work on.

l_in - Weighting factors for inner region fit.

l_out - Weighting factors for outer region fit.

Throws:

de.unihalle.informatik.Alida.exceptions.ALDOperatorException

Method Detail

init

protected void init()
             throws MTBActiveContourException

Method to properly initialize instances of this class.

Throws:

de.unihalle.informatik.Alida.exceptions.ALDOperatorException

MTBActiveContourException

updateParameters

protected void updateParameters(MTBSegmentationInterface mem)
                         throws MTBActiveContourException

Updates parameters according to given membership.

Parameters:

mem - Current segmentation object.

Throws:

MTBActiveContourException

getDerivative

protected double getDerivative(MTBSegmentationInterface seg,
                               int x,
                               int y,
                               int z)

Returns the energy derivative value at position (x,y,z).

calcEnergy

protected double calcEnergy(MTBSegmentationInterface seg)

Calculates the absolute energy value for the given segmentation.

Parameters:

seg - Segmentation to consider.

Returns:

Absolute value of energy.

calcInteriorEnergy

protected double calcInteriorEnergy(MTBSegmentationInterface seg)

Calculates the interior part of energy value for the given segmentation.

Parameters:

seg - Segmentation to consider.

Returns:

Absolute value of interior energy.

getEnergyDerivativeMaxVal

protected double getEnergyDerivativeMaxVal()

Returns the maximum possible derivative value this energy may yield.

Returns:

Maximal derivative value.

getEnergyDerivativeMinVal

protected double getEnergyDerivativeMinVal()

Returns the minimum possible derivative value this energy may yield.

Returns:

Minimal derivative value.

getMeans

protected double[][] getMeans()

Returns the average region intensities last calculated.

Returns:

List of the regions' average intensity values.

toString

public String toString()

Overrides:

toString in class Object