10.79. Erode/Dilate Bad Data

Group (Subgroup)

Processing (Cleanup)

Description

This Filter grows or shrinks regions of bad data (cells with Feature Id = 0) by one cell-layer per iteration, using standard image-morphology operations. It is a building block for cleaning up isolated noise or for compensating for boundaries that were systematically under- or over-measured by the experiment.

Fig. 1: Dilate grows the bad-data (Feature Id 0) region outward by one cell layer per iteration; Erode shrinks it, reassigning each bad cell to its majority neighbor. The Number of Iterations sets the layer count.

Dilation

Dilate grows the bad-data region outward. Each iteration changes any cell adjacent to a bad cell into a bad cell, adding a one-cell-thick layer.

Before Dilation	After Dilation

Erosion

Erode shrinks the bad-data region. Each iteration converts each bad cell into the Feature Id held by the majority of its neighbors. Ties are broken randomly. Single-cell bad regions disappear in one iteration; thicker regions take more.

Before Erosion	After Erosion

When to Use This Filter

Erode to remove small or thin regions of bad data — single-cell EBSD dropouts, salt-and-pepper noise.
Dilate to grow under-measured features. For example, EBSD scans tend to under-estimate pore size because the beam picks up signal from material below the pore when it sits at the pore edge; dilating the Feature Id = 0 region restores the true pore boundary.
Erode followed by Dilate (a morphological opening) is the classic pattern for removing isolated noise without affecting larger regions. A single erode-dilate pair will erase isolated single-cell bad regions but return larger pores to almost their original size.
Dilate followed by Erode (a morphological closing) fills small holes inside bad-data regions while preserving their outer boundary.

Iterations and Direction

Number of Iterations is in cell-layers. An iteration count of 3 grows or shrinks the bad-data region by 3 cells.
X Direction, Y Direction, and Z Direction toggle whether the morphology is applied along that axis. Disable an axis to perform anisotropic erosion/dilation – useful when serial-sectioning resolution is anisotropic (typically Z is coarser than X and Y) and you want to limit smoothing along the fine axes.

Direction Restrictions

The X Direction, Y Direction, and Z Direction parameters control which of the six face neighbors participate. With all three enabled the Filter uses all six face neighbors (-Z, -Y, -X, +X, +Y, +Z); disabling Z Direction, for example, restricts the operation to the four in-plane neighbors so that bad data grows or shrinks only within each XY slice.

Preflight Errors

The Filter refuses to run in two cases:

-14601: all three of X Direction, Y Direction, and Z Direction are disabled. At least one direction is required, otherwise there are no neighbors to erode or dilate across.
-14602: the selected Image Geometry has a dimension of 0 Cells. All three dimensions must be non-zero.

WARNING: Feature Data Will Become Invalid

By modifying cell-level data, any feature-level data that was previously computed will most likely be invalid after this filter runs. Re-run any downstream feature-level computation filters to ensure accurate results.

Required Input Sources

Cell Feature Ids – produced by a segmentation filter such as Segment Features (Misorientation) or Segment Features (Scalar). Cells with Feature Id = 0 are treated as bad.

Input Parameter(s)

Parameter Name	Parameter Type	Parameter Notes	Description
Operation	Choices		Whether to dilate or erode
Number of Iterations	Scalar Value	Int32	The number of iterations to use for erosion/dilation
X Direction	Bool		Whether to erode/dilate in the X direction
Y Direction	Bool		Whether to erode/dilate in the Y direction
Z Direction	Bool		Whether to erode/dilate in the Z direction

Input Cell Data

Parameter Name	Parameter Type	Parameter Notes	Description
Selected Image Geometry	Geometry Selection	Image	The target geometry
Cell Feature Ids	Array Selection	Allowed Types: int32 Comp. Shape: 1	Specifies to which feature each cell belongs.
Attribute Arrays to Ignore	MultiArraySelection		The list of arrays to ignore when performing the algorithm

Example Pipelines

(08) SmallIN100 Full Reconstruction
(07) SmallIN100 Final Processing
04_Steiner Compact

License & Copyright

Please see the description file distributed with this Plugin

DREAM3D-NX Help

If you need help, need to file a bug report or want to request a new feature, please head over to the DREAM3DNX-Issues GitHub site where the community of DREAM3D-NX users can help answer your questions.