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SoMultiscaleStructureEnhancementProcessing2d Class

OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d engine.

Inheritance Hierarchy

Namespace: OIV.ImageViz.Engines.ImageFiltering.TextureFilters
Assembly: OIV.ImageViz (in OIV.ImageViz.dll) Version: 10.12.3.0 (10.12.3.0)
Syntax
public class SoMultiscaleStructureEnhancementProcessing2d : SoImageVizEngine

The SoMultiscaleStructureEnhancementProcessing2d type exposes the following members.

Constructors
  NameDescription
Public methodSoMultiscaleStructureEnhancementProcessing2d

Constructor.

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Methods
  NameDescription
Public methodAbortEvaluate

Abort current processing as soon as possible.

(Inherited from SoImageVizEngine.)
Public methodCopy

Creates and returns an exact copy of the engine.

(Inherited from SoEngine.)
Public methodCopyFieldValues(SoFieldContainer)
Calls CopyFieldValues(fc, false).
(Inherited from SoFieldContainer.)
Public methodCopyFieldValues(SoFieldContainer, Boolean)

Copies the contents of fc's fields into this object's fields.

(Inherited from SoFieldContainer.)
Public methodDispose
Releases all resources used by SoDisposable.
(Inherited from SoDisposable.)
Public methodEnableNotify

Notification at this Field Container is enabled (if flag == true) or disabled (if flag == false).

(Inherited from SoFieldContainer.)
Public methodEquals
Determines whether the specified Object is equal to the current Object.
(Inherited from Object.)
Public methodFieldsAreEqual

Returns true if this object's fields are exactly equal to fc's fields.

(Inherited from SoFieldContainer.)
Public methodGet

Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.

(Inherited from SoFieldContainer.)
Public methodGetAllFields

Returns a list of fields, including the eventIn's and eventOut's.

(Inherited from SoFieldContainer.)
Public methodGetEventIn

Returns a the eventIn with the given name.

(Inherited from SoFieldContainer.)
Public methodGetEventOut

Returns the eventOut with the given name.

(Inherited from SoFieldContainer.)
Public methodGetField

Returns a the field of this object whose name is fieldName.

(Inherited from SoFieldContainer.)
Public methodGetFieldName

Returns the name of the given field in the fieldName argument.

(Inherited from SoFieldContainer.)
Public methodGetFields

Appends references to all of this object's fields to resultList, and returns the number of fields appended.

(Inherited from SoFieldContainer.)
Public methodGetHashCode
Overrides GetHashCode().
(Inherited from SoNetBase.)
Public methodGetName

Returns the name of an instance.

(Inherited from SoBase.)
Public methodGetOutput

Returns a reference to the engine output with the given name.

(Inherited from SoEngine.)
Public methodGetOutputName

Returns (in outputName) the name of the engine output (output).

(Inherited from SoEngine.)
Public methodGetOutputs

Returns a list of outputs in this engine.

(Inherited from SoEngine.)
Public methodGetStringName (Inherited from SoBase.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodHasDefaultValues

Returns true if all of the object's fields have their default values.

(Inherited from SoFieldContainer.)
Public methodIsEvaluating

Returns true if the engine evaluation is in progress.

(Inherited from SoImageVizEngine.)
Public methodIsNotifyEnabled

Notification is the process of telling interested objects that this object has changed.

(Inherited from SoFieldContainer.)
Public methodIsSynchronizable

Gets the ScaleViz synchronizable state of this object.

(Inherited from SoBase.)
Public methodSet

Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.

(Inherited from SoFieldContainer.)
Public methodSetName (Inherited from SoBase.)
Public methodSetSynchronizable

Sets this to be a ScaleViz synchronizable object.

(Inherited from SoBase.)
Public methodSetToDefaults

Sets all fields in this object to their default values.

(Inherited from SoFieldContainer.)
Public methodStartEvaluate

Evaluate engine and dependencies in another thread without blocking the current one.

(Inherited from SoImageVizEngine.)
Public methodToString
Converts this SoBase structure to a human readable string.
(Inherited from SoBase.)
Public methodTouch

Marks an instance as modified, simulating a change to it.

(Inherited from SoBase.)
Public methodWaitEvaluate

Wait for the end of engine evaluation.

(Inherited from SoImageVizEngine.)
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Properties
  NameDescription
Public propertyinImage

Input image.

Public propertyIsDisposable
ISafeDisposable interface implementation.
(Inherited from SoDisposable.)
Public propertylightness

The lightness type of structures to enhance.

Public propertyoutImage

Output image.

Public propertystandardDeviationRange

Standard deviation of the Gaussian kernel at minimum and maximum scale.

Public propertystandardDeviationStep

Standard deviation step.

Public propertystructureType

Shape of structures to extract.

Public propertytensorType

Defines whether the command will use the gradient tensor or the hessian matrix.

Public propertyUserData
Gets or sets the user data to be contained by the field container.
(Inherited from SoFieldContainer.)
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Events
  NameDescription
Public eventOnBegin

Event raised when the processing begins.

(Inherited from SoImageVizEngine.)
Public eventOnEnd

Event raised when processing ends and the result is available.

(Inherited from SoImageVizEngine.)
Public eventOnProgress

Event raised while processing is running.

(Inherited from SoImageVizEngine.)
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Remarks

Overview

The purpose of this algorithm is to enhance structures of interest from an image using a multi scale analysis. The result of this algorithm is a score image that can be used with the goal of segmenting the input image.

The SoMultiscaleStructureEnhancement filters compute a score between 0 and 1 for each pixel, 1 representing a good matching with a structure model and 0 a background pixel. This provides a powerful technique for automatically identifying structures such as blood vessels. The score can be computed either on an Hessian matrix to detect ridge structures or on a Gradient tensor for object edges and corners. The structure models available are:

  • Balls (circular structures with Hessian in 2D, spherical in 3D, object corners with Gradient tensor)

  • Rods (linear structures)

  • Plates (only available in 3D)

The principle of the algorithm can be summarized as follows :

  • A set of tensor fields is extracted from the image by filtering the image at different scales.

  • A score image is extracted from each tensor field by analyzing the eigenvalues of tensors.

  • The final score is obtained by selecting the maximum of all score images.

The following publication describes this algorithm when applied to detect Rod structures with the Hessian matrix: A.F.Frangi, W.J.Niessen, K.L.Vincken, M.A.Viergever, "Multiscale vessel enhancement filtering", Lecture Notes in Computer Science(MICCAI), vol. 1496, pp. 130-137, 1998.

Tensor Extraction

2 modes are available for computing the tensor field; the OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.GRADIENT mode and the OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.HESSIAN mode. The first one is based on the gradient tensor, the second one on the hessian matrix.

OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.GRADIENT mode

In the OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.GRADIENT mode, the gradient tensor is extracted. This tensor also referred to as structure tensor or second order moment matrix, is a matrix derived from the gradient of the image. This matrix summarizes the predominant directions of the gradient around the voxel of interest.

Where is a gaussian kernel controlling the scale of analysis.

OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.HESSIAN mode

In this mode, the tensor field is based on the extraction of the hessian matrix of the image. This hessian matrix is computed by filtering the image with the derivative of a gaussian kernel. The standard deviation of the kernel controls the scale of analysis.

Feature extraction

The parameter structureType controls the type of structure that is extracted from the tensor field (ROD/BALL). Let be the 2 eigenvalues of the extracted tensor.

The score for StructureType2D.ROD corresponds to :

This score favors anisotropic tensors.

The score for StructureType2D.BALL structures is computed as follows :

This score favors isotropic tensors.

where is the tensor norm, is a threshold which controls the blobness sensitivity, and c is a sensitivity threshold which controls the noise influence. with the maximum Hessian norm in the image.

In the OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.HESSIAN mode, the lightness parameter limits the feature extraction to dark or bright objects by analyzing the sign of eigenvalues. This parameter is ignored in OIV.ImageViz.Engines.ImageFiltering.TextureFilters.SoMultiscaleStructureEnhancementProcessing2d.TensorTypes.GRADIENT mode where tensors are positive definite matrices.

The table below summarizes enhanced feature according to the parameters
Structure Type detected feature in GRADIENT mode detected feature in HESSIAN mode
ROD strong weak straight edge ridge
BLOB strong strong edge corner/blob blob

FILE FORMAT/DEFAULT

MultiscaleStructureEnhancementProcessing2d {
inImage NULL
tensorType HESSIAN
standardDeviationRange 1.0f 3.0f
standardDeviationStep 1.0f
lightness BRIGHT
structureType ROD
}

Library references: structureenhancementfilter

See Also