Module: Additional Segmentation CAC ()

Description:

Segments the voxels in a phase of interest in the segmented input file, by applying CAC segmentation on the intensities from the data in the input tomogram data. The phase of interest will be divided into 2 phases by this filter, so all the phase values greater than the phase of interest are incremented by one, to accommodate the extra phase. This filter should be used in preference to 3-phase segmentation as it simplifies the parameter choice.

Connections:

Segmented Data [required]
The segmented data to use for the segmentation. This input must be a 8-bit unsigned Label Field. Besides, this data must contain less than 2 billion voxels.

Tomographic Data [required]
The original data used to generate the first input. Supported type is 16-bit unsigned grayscale image (Uniform Scalar Field). Besides, this data must also contain less than 2 billion voxels.

Warning: Segmented Data and Tomographic Data must have the same dimensions and voxel size.

Ports:

Phase of Interest

This is the phase that the filter works on - all other phases in the segmented file and the corresponding voxels in the tomographic file are ignored.

Lower Threshold

Cut off value below which the data is set to void in the initial thresholding, if the gradient is also lower than the lower gradient threshold.

Upper Threshold

Cut off value above which the data is set to solid (grain) in the initial thresholding, if the gradient is lower than the upper gradient threshold.

Gradient Threshold

Activate the gradient threshold. In addition to thresholding on intensity, threshold on gradient.

Void Gradient Threshold

Initial gradient threshold value for 'void' voxels - those with intensity values below the Lower Threshold. If the gradient is above this value the voxel is set to undecided in the initial thresholding.

Grain Gradient Threshold

Initial gradient threshold value for 'grain' voxels - those with intensity values above the Upper Threshold. If the gradient is above this value the voxel is set to undecided in the initial thresholding.

Advanced Threshold

Tight thresholds may aid difficult segmentations with disconnected small lower and higher intensity regions. Linear gradients provide a more dynamic use of gradient information.

Tight Lower Threshold

Cut off value below which the data is conditionally set to void before the second stage. Regions set to void in this stage remain void only if they connect to other regions set to void in the initial thresholding.

Tight Upper Threshold

Cut off value above which the data is conditionally set to solid before the second stage. Regions set to solid in this stage remain solid only if they connect to other regions set to void in the initial thresholding. Should be lower than Upper Threshold.

Tight Void Gradient Threshold

The secondary gradient threshold for the void phase. Voxels with intensities less than the lower tight threshold but with higher gradient values than this parameter will be put in the undecided group otherwise they will be set to maybe pore.

Tight Grain Gradient Threshold

The secondary gradient threshold for the grain phase. Voxels with intensities greater than the upper tight threshold but with higher gradient values than this parameter will be put in the undecided group otherwise they will be set to maybe grain.

Inner Lower Threshold

Cut off value below which the data is set to void before the second stage if its gradient falls below a decreasing gradient parameter. At the Lower threshold the gradient parameter is the set gradient. This decreases linearly to zero as the intensity values increase to this lower tight threshold.

Inner Upper Threshold

Cut off value above which the data is set to solid before the second stage if its gradient is below an increasing gradient parameter. At the upper tight threshold the gradient is zero. This increases linearly to the set gradient when the intensity values reach the upper threshold.

Inner Void Gradient Threshold

The secondary gradient threshold for the void phase. Voxels with intensities between the lower and inner lower thresholds will be set to void if the gradient is below a decreasing value. This value is equal to the inner void gradient threshold at the first intensity threshold and drops to zero linearly to the inner lower threshold.

Inner Grain Gradient Threshold

The secondary gradient threshold for the grain phase. Voxels with intensities between the upper and inner upper thresholds will be set to grain if the gradient is below an increasing value. This value is equal to zero at the inner upper threshold and increases linearly to the inner grain gradient at the upper intensity threshold.

Void Grain Speed Ratio

This is the ratio between the speed of growth of the void seed regions relative to the grain regions. Values less than one retard the void phase relative to the grain phase; values greater than 1 speed it up. Normally this should be left at 1.0.

Unassigned Voxel Policy

If the segmentation is taking place in a multiply-connected domain, then it's possible to have some isolated components of the domain that don't have any seed values. These regions will always end up as undecided. If you are using a multiply connected domain, e.g. as part of a multi-stage segmentation, then you may wish to assign a particular phase to these regions, often a phase with a low gradient threshold. For normal segmentations this should be left to -1 which will means that unassigned voxels cause an error.

Gradient Divisor

The higher this value is, the less influence the gradient will have on the front propagation speed. The default value should be sufficient in almost all cases.

Gradient Exponent

Larger exponents increase the speed sensitivity to the gradients. Normally best left at the default value.