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Advanced Point Cloud Filtering in TBC for Mobile Mapping Applications

Sampling a point cloud in a smart way can remove noise and reduce the size of a needed point cloud export. For example, it can be used in the creation of a road surface starting from a mobile mapping data acquisition.

The workflow below covers how to sample the point cloud data with the new Advanced Point Cloud Filtering tool available in Trimble Business Center Point Clouds TAB.

TBC version 2023.11 was used for this example with a dataset collected with the Trimble MX9 mobile mapping system.

Tools & Procedure

From Point Clouds TAB in the ribbon, select the Advanced Point Cloud Filtering tool.  

From this tool window, select the Point Cloud region you want to filter, and assign a name to the new Point Cloud Region that will be created by the tool:

Specify the filtering criteria. The tool will create a grid of points based on cells of defined size (Cell size). One point per cell will be included.

In the Filtering Options box, specify the filtering strategy for the elevation; pick an option from the dropdown menu. Choose the Average elevation of the point inside the specific cell, minimum elevation or maximum elevation of the highest or lowest point in the cell. 

The Average elevation is the default option and will allow you to create a new point in the center of the cell. In general the Average elevation option will create a smoother surface.

In case of Actual location, the point's horizontal location is not changed. This option is only available when using minimum and maximum elevation criteria in the Filtering Strategy.

In the case of the center of the cell, the point is moved to the horizontal center of the sampling cell.

The point cloud can also be filtered along a polyline by applying lateral and vertical offsets. In this example, the road center line was used as a reference polyline. A horizontal offset of 3.2 meters was applied.

In the Vertical Offset Field, enter the vertical distance above and below the polyline to which you want to apply the filter. If no vertical offset distance is entered, the filter will be applied to all points above and below the polyline within the horizontal offset distance.

Click on Filter at the bottom of the Advanced Point Cloud Filtering tool window.

When the filtering task is completed, in the View Filter Manager, the new region is visible in the Point Cloud Regions group.

In the Advanced Settings of the Advanced Point Cloud Filtering tool, there is an option (minimum point cloud density) to not include cells with sparse points, and an option (Outlier Point Filter) to remove noise and spikes from the sampled data. The minimum number of points per cell can be customized depending on your project parameters.  

Learn more about Trimble mobile mapping solutions and Trimble Business Center office software.