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Point to Point

Point to Point

Owned by Omar Lamrani
Last updated: Mar 05, 2025 by Reza Mahmoudi Kuohi
2 min read

Menu: File / Registration / Point to Point

The Point-to-Point Registration tool aligns a point cloud with a reference point cloud by selecting corresponding points in both datasets. Using a minimum of three corresponding points, the algorithm calculates the necessary translation and rotation to correctly reposition the moving point cloud. The adjustment is performed using the least squares method to minimize errors.

How to Use the Point-to-Point Registration Tool

1. Selecting Files

  • Choose the reference file and the file to be moved from the drop-down list.

  • Click “Show” to display both point clouds:

    • The reference cloud appears in the main window.

    • The cloud to be moved is shown in a secondary window.

2. Picking Corresponding Points

  • Click “+” to add a new control point.

  • Select “Pick reference point” and click on a point in the main window. The XYZ coordinates will be recorded in the table.

  • Find the corresponding location in the secondary window, then select “Pick to move point” to assign a matching point. The coordinates for this point will also be added to the table.

  • At least three corresponding points are required for the registration to function, but seven or more points are recommended to improve accuracy and assess residual errors.

  • Best practices:

    • Distribute control points across different sectors and elevations.

    • Identify and remove points with high residual errors by unchecking them in the table.

    • Use the “X” button to delete selected control points.

3. Validating and Applying the Transformation

  • Click “Validate” to analyze the transformation. The software will display:

    • Differences between corresponding XYZ points.

    • Standard deviation of the transformation.

    • Calculated translation and rotation values.

  • If necessary, adjust the selection by adding, removing, or refining control points.

  • Once the results are satisfactory, click “Apply” to preview the transformed point cloud in the main window.

4. Finalizing the Registration

  • Click “Back” to undo the transformation.

  • Click “Reindex and Reopen” to permanently apply the transformation and regenerate the point cloud index.

  • If you apply the transformation and close VisionLidar, the index will be automatically updated when reopening the project.

5. Exporting a Registration Report

  • Click “Report” to generate a .TXT report containing:

    • All selected control points.

    • The standard deviation of the transformation.

    • Applied translation and rotation values.

Using an External Reference File for Registration

  • Enable the “External File” option to use an external reference file instead of a previously loaded point cloud.

  • Select the external file, and the “to move” point cloud will be aligned accordingly.

  • When using an external reference file, clicking “Reindex and Reopen” will generate a new LAS file with the updated coordinates.

 

 

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