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	Scale current LUT to new image: Bool
End (alphaEnd): Double	Start (startColor): Color
Image Max Value: Double	Start (alphaStart): Double

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 no image attached).

VOI LUT Function is SIGMOID

name: isSigmoidVOILUT, type: Bool, persistent: no

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

Scale current LUT to new image

name: scaleLUTForNewImage, type: Bool, default: FALSE, deprecated name: useRelativeIfNoInputImage

If checked, the scale of the current LUT is applied to any newly connected image.

In other words, if the LUT is defined using absolute values, its relative appearance remains unchanged when the input image changes.

If the input image is disconnected temporarily, the previous scaling is stored and reapplied once a new image is connected.

Keep this option unchecked if you want to use the same absolute LUT for different images. Otherwise, on disconnecting the input image, a relative LUT is computed and on connecting a different image, this relative LUT is used to compute the next absolute LUT. This results in having always the same appearance for images with a different image value range.

If a relative LUT is used by Relative, this setting has no effect and is therefore disabled in the GUI.

If checked, Compute LUT on each image change would overwrite the new LUT, so it is also disabled in the GUI.

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 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.

If checked, Compute LUT on initialization has no effect and is therefore disabled in the GUI.

Compute LUT Anew

name: computeLUTAnew, type: Trigger

When pressed, a new default LUT is computed using the input image’s DICOM tags.

The following DICOM tags are used: 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

If checked, 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