Target-based Registration of Point Clouds

Automatic target extraction requires data collected with a Trimble X series instrument (X7, X9). Manual workflows support any kind of point cloud data.

Prerequisites:

See the Subscription Plans page. For a license matrix by command, see the License page in the TBC Community. Also see View and manage licensed features.

To extract targets from a scan:

  1. Select Target-Based Registration in Point Clouds > Registration.
  2. In the Extract tab under Target types, do one of the following:
    • If your targets are spherical, select Spherical, then choose the Diameters of your sphere.

      Click the Custom checkbox to enter a custom diameter for your sphere.

      Note: You can select more than one sphere diameter.

    • If your targets are flat, select Black and White Flat, then enter a Width in meters.
  3. Under Select stations, select the stations to extract your targets from.
  4. Select a Reference station from the dropdown list.
  5. Click Extract.

    The specified targets are extracted, fit, matched, and registered from the scan. A progress bar displays at the bottom of the window showing the progress of the extraction. Once finished, the Analyze tab and the Station View opens. You can also see the results of the extraction in the Plan View.

    Note: The Extract button extracts targets that fit the parameters and applies the initial registration for stations based on the extracted targets. Manual creation will not be applied until you click the Register button.

  6. Click Register to compute and apply transformations for each station. Clicking Register changes the target observations from foresight to backsight, ensuring that target points adjust the position of the stations.

To analyze targets in a scan:

After the targets have been extracted, you can begin the analysis process.

  1. Click the Analyze tab.
  2. Click an observation in the Target Observations list to open a Target View.

    The Target View displays only the selected observation and its fitted point cloud.

  3. Follow these instructions to edit the target observations:

    To designate new target observations

    To refit a target observation with a point cloud

    To match or unmatch target observations

    To delete a target observation

    Related topics

To designate new target observations:

If the extraction process missed any targets, you can designate new target observations.

  1. Click Create.
  2. Choose Spherical or Black and White Flat from the dropdown list.
  3. For spherical targets, select the diameter from the dropdown list.
  4. To pick a single target observation:
    • Click Pick.
    • In the Plan View window, click a target observation.
  5. To select multiple target observations:
    • Click Poly-select.
    • In the Station View window, draw a boundary around the target observations you want to select.

To re-fit a target observation to a point cloud:

  1. Select a target observation from the Target Observations list.
  2. Click the Re-fit toggle. The Target View window opens.
  3. In the Target View window, select any outlier points which do not correspond to the target observation.
  4. Use the Keep In/Keep Out buttons to filter out the outlier points.
  5. Click the Re-fit button to align the target observation geometry more accurately with the filtered point cloud.
  6. For black-and-white observations, the selection control lets you manually select the observation's geometry in the Target View window and use two axis-locked grips to align the geometry center with the point cloud center.
  7. Use the Height text box to edit the target height value.
  8. Click Register to use the matched targets to compute and apply the transformations for all non-reference stations.

To match or unmatch target observations:

  1. Click Match/Unmatch.
  2. Select a target from the Target observations list, then do one of the following:
    • To match the target observation with another target observation, click Match with.

      In the Target-based Registration window, select a target observation and click OK.

    • To disassociate the selected target observation, click Unmatch.
    • To reset a previously matched target or automatically match all observations, click Match all.

To delete a target observation:

  1. Select a target observation from the Target observations list.
  2. Click Delete.

    The target observation is automatically deleted from the Target observations list.

  3. Click Register to save and close.

Related topics

Georeference Point Cloud Scans

Register, Refine, and Georeference Point Cloud Scans