morphological_grow_shrink

Note

This page is a reference documentation. It only explains the function signature, and not how to use it. Please refer to the Habitat Guide and Python API guide (v2.0) for usage.

morphological_grow_shrink(mask: ndarray, grow_mm: float, spacing_xyz: Sequence[float] = (1.0, 1.0, 1.0), connectivity: int = 1) → ndarray[source]

Uniformly dilate (grow_mm > 0) or erode (grow_mm < 0) a mask.

This is MIRP perturbation_roi_adapt_size: the systematic component of inter-rater contour variability, where one observer consistently traces slightly larger or smaller than another. Only the mask changes; image intensities are untouched. Applied per foreground label so a multi-label ROI grows each region instead of merging them.

Parameters:

  • mask – Integer / boolean label array in (z, y, x) order; 0 is background.

  • grow_mm – Physical radius in millimetres. Positive dilates, negative erodes, zero returns an unchanged copy.

  • spacing_xyz – Voxel spacing in SimpleITK (x, y, z) order, used to convert millimetres to an iteration count.

  • connectivity – Structuring-element connectivity in {1, 2, 3}; 1 is the 6-connected face neighbourhood (the conservative, MIRP-like default).

Returns:

A new label array, same shape and dtype as mask.

Raises:

ValueError – If erosion removes every foreground voxel (the ROI would vanish), or connectivity is outside {1, 2, 3}.