Scanning Tip of the Week: Registration Techniques for Trimble Perspective Software
Trimble® Perspective™ software has revolutionized laser scanning workflows by allowing in-field point cloud registration. The built-in Inertial Measurement Unit (IMU) orients the scanner while moving between scan locations to give the initial cloud alignment. After completing the station scan, the point cloud is downloaded and processed for registration. Auto-registration is performed and is typically successful without any user input. But what do you do when auto-registration is unsuccessful? The example below shows a Check Registration warning for a large error value. Correcting this registration error can be done using manual alignment.
First, select the station that is experiencing the registration issue. Be sure to be in the 2D view and select Register.
The scans colors will appear as white and blue, denoting the reference cloud and moving clouds respectively. The reference scan will be held fixed to its current location, while the moving scan will be shifted to align to the reference scan.
Selecting within the blue circle surrounding the moving cloud station will allow the user to translate the point cloud. When this selection is made, the moving point cloud changes from blue to orange.
Selecting the blue circle itself will allow the user to rotate the moving point cloud. Tip: Moving your finger further away from the blue circle after selection will allow a slower rotation of the moving cloud.
Once satisfied with the alignment, press Register. As long as sufficient overlap and alignment are present, the registration should now be successful.
Another method to correct registration alignments is using the Split View mode in Trimble Perspective. This feature is also found by highlighting a station and selecting Register while in 2D viewing.
This will bring up a station-based view of the reference and moving clouds in a split screen window. Trimble Perspective will prompt the user to select two common points between the two scans to allow registration.
Some common points to look for include light standards, curbing, building corners, or other features that are easily recognizable.
With the two common points selected, click Register to complete the alignment between the two clouds. The example here was able to complete the registration with an error of 0.7 mm.
Hopefully these tips help you with your project workflows, and as always, keep on scanning.
Learn more: Trimble Perspective software