RampLUT

MLModule

genre	LUT
author	MeVis Medical Solutions AG
package	MeVisLab/Standard
dll	MLLUTTools
definition	MLLUTTools.def
see also	LUTPrimitive, LinearLUT, TableLUT, ChangeLUTColor, LUTInfo, LUTCurve, ApplyLUT, SoMLLUT, Window
keywords	lookup, table, center, width, level, window

Purpose

The module RampLUT generates an RGB and alpha ramp lookup table (LUT) object.

The LUT can be used with the ApplyLUT module or within 2D/3D viewers (in conjunction with SoMLLUT). The two ramps for RGB and alpha channels can be parametrized independently.

Usage

Select parameters for the RGB Ramp and the Alpha Ramp. For both ramps, specify Center and Width, as well as Start and End color or alpha value.

Connect the outLUT output field to a SoMLLUT module to use the LUT in a 2D/3D viewer, or to an ApplyLUT module to apply the LUT to an ML image.

The module also has an ML image input; if a valid ML image is connected, the module RampLUT can set a default LUT based on the image’s min/max value or, if existing, on the LUT set in the DICOM tags.

Details

See LUT Functions for general information about ML lookup tables.

For the exact handling of the DICOM Window Center and Window Width tags see the Details section of DicomLUT.

Windows

Default Panel

Input Fields

input0

name: input0, type: Image

Output Fields

outLUT

name: outLUT, type: LUTFunction(MLBase)

Parameter Fields

Field Index

Center (center): Double	Image Min Value: Double	useCorrectDicomLinearLutInterpretation: Bool
Center (alphaCenter): Double	Image Range Max Value: Double	VOI LUT Function is SIGMOID: Bool
Compute LUT Anew: Trigger	Image Range Min Value: Double	Width (width): Double
Compute LUT on each image change: Bool	Image valid: Bool	Width (alphaWidth): Double
Compute LUT on initialization: Bool	Relative: Bool
End (endColor): Color	Start (startColor): Color
End (alphaEnd): Double	Start (alphaStart): Double
Image Max Value: Double	Use relative LUT if no input image: Bool

Visible Fields

Relative

name: relative, type: Bool, default: TRUE

If checked, the generated LUT is relative, i.e. the index value interval [0..1] is rescaled to the true image value range before applying the LUT. If the LUT is absolute, on the other hand, the image values are used as index values directly, without rescaling.

Center (center)

name: center, type: Double, default: 0.5

Sets the center index value of the ramp, either as an absolute image value or relative to [0..1].

Width (width)

name: width, type: Double, default: 1

Sets the width value of the ramp, either as an absolute image value range or relative to [0..1].

Start (startColor)

name: startColor, type: Color, default: 0 0 0

Sets the color used for index values below the start of the ramp (i.e. index <= center-width/2).

End (endColor)

name: endColor, type: Color, default: 1 1 1

Sets the color used for index values above the end of the ramp (i.e. index >= center+width/2).

Center (alphaCenter)

name: alphaCenter, type: Double, default: 0.5

Sets the center index value of the ramp, either as an absolute image value or relative to [0..1].

Width (alphaWidth)

name: alphaWidth, type: Double, default: 1

Sets the width value of the ramp, either as an absolute image value range or relative to [0..1].

Start (alphaStart)

name: alphaStart, type: Double, default: 0, minimum: 0, maximum: 1

Sets the alpha value used for index values below the start of the ramp (i.e. index <= center-width/2).

End (alphaEnd)

name: alphaEnd, type: Double, default: 1, minimum: 0, maximum: 1

Sets the alpha value used for index values above the end of the ramp (i.e. index >= center+width/2).

Image valid

name: isImageValid, type: Bool, persistent: no

Shows whether the attached image is valid (or if there is an image attached).

VOI LUT Function is SIGMOID

name: isSigmoidVOILUT, type: Bool, persistent: no

Indicates if the VOI LUT Function tag of the input image is set to SIGMOID. Nonetheless the module will always create a linear ramp LUT.

Use relative LUT if no input image

name: useRelativeIfNoInputImage, type: Bool, default: FALSE

If checked, the module uses a relative LUT in [0..1] if no input image is attached.

If there was an input image attached and the module used an absolute LUT and the image is detached while this flag is checked, the module uses the same LUT as before just in relative bounds.

Compute LUT on initialization

name: shouldComputeLUTOnInitialization, type: Bool, default: TRUE

If checked, the module computes the LUT automatically based on the input image on initialization, i.e., after a saved network has been loaded. Otherwise, the stored LUT values (center, width) are just used.

Compute LUT on each image change

name: shouldComputeLUTOnEachImageChange, type: Bool, default: FALSE

If checked, the module computes a default LUT on each update of the input image.

Compute LUT Anew

name: computeLUTAnew, type: Trigger

If pressed, the LUT is computed anew on base of the input image’s DICOM tags.

The DICOM tags used to compute the LUT are: WindowCenter, WindowWidth, SlopeIntercept, and SlopeRescale.

Image Min Value

name: imageMinValue, type: Double, persistent: no

Shows the input image’s minimum value (or 0 if no image is attached).

Image Max Value

name: imageMaxValue, type: Double, persistent: no

Shows the input image’s maximum value (or 1 if no image is attached).

Image Range Min Value

name: imageRangeMinValue, type: Double, persistent: no

Shows the minimum value of the image value range. This is always 0.

Image Range Max Value

name: imageRangeMaxValue, type: Double, persistent: no

Shows the maximum value of the image value range.

Hidden Fields

useCorrectDicomLinearLutInterpretation

name: useCorrectDicomLinearLutInterpretation, type: Bool, default: TRUE

Flag to determine that the window center shall be reduced by 0.5 and the window width by 1.0 which leads to the DICOM conform calculation for linear LUTs. This is only relevant when the VOI LUT Function tag is set to LINEAR.

legacyValue: False