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tono/docs/nodes/Mark Disconnected.md
2026-04-04 00:25:53 -07:00

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Mark Disconnected

Mark topologically disconnected (isolated) surface regions. A morphological opening followed by closing builds a smooth defect-free reference surface; pixels whose deviation from that reference exceeds the sensitivity threshold are flagged. Equivalent to Gwyddion's mark_disconn.c module.

Inputs

Name Type Required Description
field DATA_FIELD Yes Input surface to analyse for disconnected regions

Outputs

Name Type Description
mask IMAGE Binary mask (0/255) marking detected disconnected regions

Controls

Name Type Default Description
defect_type dropdown positive Which direction of outliers to detect: positive (bumps), negative (pits), or both
radius INT 5 Morphological filter radius in pixels (1--100). Larger values smooth over bigger features
threshold FLOAT 0.1 Sensitivity threshold as a fraction of the max residual range (0.001--1.0). Lower values detect smaller defects

Notes

  • The algorithm applies grey-scale morphological opening then closing with a disk structuring element to produce a defect-free reference. The difference between the original surface and this reference highlights isolated regions.
  • Increase the radius to ignore larger surface features and only flag truly disconnected regions.
  • Lower the threshold to catch subtler defects; raise it to reduce false positives.
  • The resulting mask can be fed to Laplace Interpolation or Fractal Interpolation to fill the detected regions.