Using the Scanner
Starting the Scan
Once the scanner has been turned on, calibrated, and mounted, make a new dataset.
Set the scanner to manual mode (preferred).
Start the scan and begin walking your path when ready. Take photos every 1-2m.
If you close the dataset you will not be able to add to it again.
However, you can combine two datasets after extracting them from the scanner during processing stages.
Interface
Begin the scan only after you have understood the interface and spatial requirements of the VLX.
New dataset > name your dataset > start mapping
This screen will now show up (LIDAR mapping of your environment)
Use the pause/start button when
people or moving objects are entering the environment to minimise noise and alignment issues.
the device is being where you do not want to scan or take photos, but still want to continue capturing in the same Dataset
Note: In pause mode, only the 3D scan process is paused. Localization is always running. To avoid impairing the quality of the recorded map, do not move faster or less carefully than normal.
Caution: If the speed indicator turns red, it means that the user is moving so fast that the quality of the dataset might suffer. Move or rotate more slowly.
Photo Settings
Point cloud colour is achieved by projecting a photo onto the point data.
There are two methods for taking photos;
Manual: Trigger the photo manually using the button below the screen / above the handle.
Automatic: Once you travel the specified distance, the scanner will automatically take photos (adjustable in settings). You can take additional photos manually while automatic mode is switched on.
These options can be selected in settings OR if you have already started scanning, but tapping the button displayed below
You can review photos in the photo viewer. Here you can also delete photos containing unwanted elements to exclude them from the colour information.
It is recommended to take photos every 1m for good point-cloud colouring. In more open spaces a photo every three meters is sufficient.
Scanning Overview
Preparing the site
Open doors in advance and use door stoppers to keep them open where possible
Clean the environment from movable objects within the planned trajectory (e.g., chairs)
Avoiding busy times, keeping the number of pedestrians and cars within the scene as low as possible.
Pause a scan if an unwanted object approaches or when a door needs to be opened.
Walking techniques
Speed
Walk slow and gently. Fast or abrupt movements can reduce point cloud density and image quality. The scanner will let you know when you are walking to fast when the speed bar becomes red.
Distance and time
Aim for a minimum distance of 1 m from walls and other objects for safety and to achieve a high quality panorama image. The best quality images and point clouds are captured 1 - 10 m away from objects.
If you are too close to an obstruction, the VLX will give you a warning with a loud honk. In this case, stop moving forward and determine what caused it.
Keep the dataset under 1 hour as the VLX will run out of battery. The longer a dataset is, the better alignment will be.
If you pause scanning, you can move around within the already recorded point cloud. Moving outside this will cause misalignment.
General Approach
General
Walk around an object of interest multiple times.
Walk in both directions through a corridor.
Rotate 360° in corners and tight spaces.
Lift the device overhead to scan on top of or above objects, such as cabinets
Crouch down to scan below objects, such as below window sills.
Multiple levels
The VLX will not register changes in elevation via lift. You must scan up and down stairs to create a multi-level dataset.
Walk both up and down stairs.
Rotate 90° to the left and right before going up or down stairs.
You do not have to go up and down stairs consecutively, however, ensure you travel both directions in the duration of your scan.
Doorways
You may need to bend your knees, or remove the VLX from your shoulders to fit under doorways.
Bend your knees until you can fit underneath the obstruction without hitting the NavVis VLX; or
Tilt the device in front of you. Hold the frame securely and remove the hooks from your shoulders. Leave the belt hook in the holster.
Be wary of the VLX's added height. Once worn, move slowly and stay clear of obstructions on the side and overhead.
Other Techniques
Pausing Scans
Pausing scans can be useful when moving objects appear in the scanning space
For example, if you are scanning a building, you may want to pause scanning when people enter to avoid messy point clouds in your scan.
When a scan is paused, do not move outside the already scanned area of the site, which will be visible on the VLX dashboard.
During post processing, you are able to remove some areas of the scan and delete photos that you do not want in the colour information.
Scanning Large Spaces
When scanning large open spaces, it is recommend that you move in structured rows.
This helps the sensors maintain points of reference that align the scan.
If there are spans of space with no variation or repeating elements, place objects such as markers or cones to help the scanner align. The VLX generally struggles to accurately scan spaces such as these.
Errors
Follow this link to troubleshoot any errors that appear during scanning.
Issues covered include:
Mapping and SLAM
Warning and errors
Other more specific issues you may encounter
Multiple Datasets Required
If multiple datasets are required, simply start a new dataset and process them all separately. They can then be combined via external software like CloudCompare.
Moving Objects
The VLX scans environments via Simultaneous Localisation and Mapping (SLAM)
This means that the VLX uses the environment to continuously locate itself by referencing nearby objects
Therefore, when there are many moving objects, it has issues with alignment and accuracy.
If there is a single moving object within the scene, the SLAM algorithm will most likely continue mapping normally.
In the scenarios listed below, SLAM is particularly problematic. This can be observed wen data is overlaping on the dashboard.
Repetitive or featureless environments (e.g. tunnels, corridors, open fields or streets, forests, fences, repetitive building outlines)
Too many moving structures (Aim to have more fixed elements than moving elements in the environment)
Point Cloud Noise
When viewing the point cloud of the scan, you may notice floating points not part of a scanned object. This is referred to as point cloud noise and can be a result of obstructions, moving objects or inaccurate scanning.
The VLX has inbuilt filter algorithms which reduce from objects that remain continuously moving for the duration of the scan.
If these objects stop at any point in the scan, they will be included in the point cloud data, and can be identified as points hovering in otherwise empty space.
This can be cleaned in the post-processing stage.
Control Points
This section provides an overview of using control points while scanning.
What are control points?
Control points are physical markers places on areas of the site.
They are linked to a coordinate system and generally require a surveyor to locate.
You do not need to use control points with the VLX, however, they aid in alignment and mapping in large or complicated sites.
Using control points
Place control points every 5 meters, avoid placing in straight lines. To improve accuracy, place them at corners and at the ends of corridors.
They can be located on the ground, at hip height (on walls) or at shoulder height.
Start scanning normally, and when you approach a control point, follow the instructions below to add it to the VLX map.
Adding control points
Tap on the top-centre control point icon
If relevant, name the control point with relevant details. The name of the control point on the VLX should match to the physical control point on site. Proceed to the next page.
Take the VLX off and align the arrow on the belt clip to the control point
Press the buttons highlighted below to add control point
Press continue and re mount the VLX to keep scanning
Hot Swapping Natteries
If the battery is running low, you can switch out the batteries one by one to allow near-continuous scanning. This is called hot swapping.
Removing both batteries will result in loss of power. This will delete your data.
There must always be one battery with charge powering in NavVis VLX.
Follow these steps to hot swap the batteries
Pause scanning. The VLX requires both batteries to actively scan.
Check the battery charge levels on the top left corner of the dashboard.
Push the blue battery release to remove the battery.
Push a charged battery in its place.
Repeat for the other side.
Continue scanning once batteries are replaced.
It is best to get another person to do this for you to avoid dropping and damaging the batteries.
Even though the scan is paused, the time is included in the dataset. Avoid exceeding 60 minutes of scanning within a dataset.
Finish Procedure
Ensure you have saved the scan by pausing and tapping the save icon on the bottom right of the dashboard.
Remove the VLX and place it on a flat surface.
Switch off the NavVis VLX by pressing the power On/Off button on the side of the NavVis VLX.
Once off, place shoulder hooks into the box first
Remove batteries and SSD and place into allocated slots within the VLX box
Loosen screws with the provided torque wrench
Fold the VLX into place
Put the belt and any other items inside the box and close it securely
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