Spine Poly-rigid Deformation

Summary

Initializes a poly-rigid deformation on a CT volume using vertebra-defined rigid regions from a spine annotation (source). Use this to model articulated spine motion for registration/simulation or to pre-initialize deformation from anatomical structures.

See also: SpineData.

Compatible data

  • Requires: SharedImageSet (volume), AnatomicalStructureCollection (source SpineData), optional AnatomicalStructureCollection (destination SpineData).

  • Implicit assumptions: source spine defines vertebra regions consistently; missing vertebrae lead to missing rigid sections.

Output

  • A configured PolyRigidDeformation with control points/rigid sections, and distance volume(s).

Key parameters

  • Chamfer Distance (bool): Use chamfer distances when computing distance volumes.

  • Sphere Mode (bool): Sphere approximation for inverse displacement (fast, approximate).

  • Mode (enum): Forward/backward mode for GlPolyRigidDeformation. Forward is recommended for performance.

  • Inversion Steps (int): Iterations for inverse displacement.

Workflow

  1. Provide the volume and the source spine collection (and destination if available).

  2. Run the algorithm; it computes distance volumes and initializes rigid sections per vertebra.

  3. Adjust mode/inversion steps as needed.