CustusX  16.5
An IGT application
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Registration Method Plugin: PointCloud

Surface to Pointer I2P Registration

Use a tracked pointer to indicate the skin surface, then register to a skin surface segmented from image data.


  • Make sure an initial patient registration is in place (this method is local).
  • Segment a skin surface from your image data, then set the surface as fixed data.
  • Start recording, then move the pointer over the skin area in question. The movement should generate a surface that contains enough variation such that it can be matched to the segmented surface.
  • The two surfaces are registered to each other using the ICP Algorithm , and the patient registration is updated.

How to get a surface from your image

A nice skin segmentation algorithm can be found in Slicer3D. Use the following procedure to use it:


  • Send volume to Slicer3D using Data Transfer Widget . Set RAS as protocol when sending to Slicer3D (CustusX uses LTS). Alternatively, file transfer can be used. Slicer3D IGTLinkIF must be configured to receive the volume.
  • Create foreground image using Slicer3D: Foreground masking Module (BRAINS).
  • Run a contouring on the mask using the Model Maker Module in order to get a surface.
  • Send surface back to CustusX using the same OpenIGTLink connection used earlier.

Point Cloud I2P Registration

Use the ICP Algorithm to perform a patient registration.

  • The fixed data is a point cloud in the reference space.
  • The moving data is interpreted as being in the Patient Reference space, i.e. acquired physical data.
  • The algorithm will perform a registration, then modify the patient registration (see Specific Spaces ) to match the two data sets to each other.

This is a generalization of the Surface to Pointer I2P Registration .

Intended usage: Surface-to-surface registration. Extract the surface of an image, then acquire the same surface using physical aquisition such as a laser scanner. Registration will move the surface onto the physical data.