Scanning Tips

The following describes some tips for achieving an accurate scan.

Walking Speed

Walk at a slow pace. This will help to ensure good quality.

• Rotating quickly and generally moving too fast will result in a lower density point cloud.

• Moving too quickly also degrades the data quality in terms of accuracy, and it increases the likelihood of issues with SLAM. You should avoid fast accelerations, rapid slowdowns and sudden movements, abrupt stops or fast rotations. It is better to move slowly and with gentle, continuous movements.

• When taking panoramas, do not rush, make sure you stand still without any motion, since motion blur cannot be compensated for.

Distance from Objects

The best quality panoramas and point clouds are captured from 1m to 10 m away from objects. Moving closer to an object (less than 1 meter away) degrades the quality of the panoramic image and point cloud.

Multiple Perspectives

Scan objects and take panoramic images from many different perspectives for a more complete point cloud:

• Walk up and down the stairs.

• Walk in both directions up and down a corridor taking panoramic images from both directions.

• Rotate 360° in corners and tight spaces.

• Walk around an object of interest multiple times.

• Rotate 90° to the left and right before going up or down stairs.

• You can lift the device overhead or hold the device lower to scan on top or below objects.

Small Rooms

Images captured in small and narrow spaces are prone to stitching errors, as walls and objects may be too close to be accurately captured. Try the following when scanning in small rooms:

• Scan the room from the outside by rotating 90° to the left and to the right in front of the room.

• Enter the room and rotate 360° to capture all of the environment. Make sure the Accuracy Bar stays as green as possible.

Recording many images from different positions will minimize the possibility to have the object of interest in the stitching seam.

Scanning Duration

The recommendation is to keep a dataset to less than 45 minutes. Datasets of this duration are best considering alignment effort and post-processing duration.

Scanning Corridors

The device can "hold on" to structures behind it, if not hidden by operator’s head. In some cases, like long corridors, it can improve SLAM if the device is held sideways so that the Laser Scanner is able to see the beginning and end of a corridor.

Scanning Outdoors

• Use loop closures every 15 - 30 m, in an outdoor situation they "feel" smaller than they actually are. Check the Quality Map on the screen for the executed loop sizes.

• Walk and turn especially slow. Naturally, people tend to speed up outdoors and underestimate the distances they are walking.

• If you notice an area that does not contain unique features or structures that the scanner can find, you can artificially enrich them with colorful objects. Move cars or boxes to add structures to your mapping space or open doors and windows in different ways to create differentiation points.

Do Not Scan in the Rain

The device is protected against dripping water. However, do not scan with the device when it is raining. If water gets on the camera lenses and the laser scanners, the scanning results will be affected.

If water gets on the device, follow these steps:

1. Leave the device on the harness, do not tilt the device.

2. Save the dataset.

3. Move to a sheltered location out of the rain.

4. Dry any water that has accumulated on the device before putting it down.

5. Place the device on a dry surface and turn it off.

6. Dry all the water from the camera lenses, laser scanner, and device housing.

7. To continue scanning, make sure that no water went into the device where the battery and memory are inserted. Then start a new dataset.

8. Before you put the device away, dry it thoroughly using a clean and dry microfiber cloth.

9. If you are back in the office, unpack the device and let it dry overnight on a desk.

Dusty Environments

The device is protected against dust during operation.

If you scan in an environment with a lot of dust, the air intake and outlet vents on the device prevent dust from entering:

• The air intake vents have filters that keep dust out.

• The air outlet vents constantly blow air, which keeps dust out.

If dust gets on the camera lenses and the laser scanner, the scanning results will be affected. Follow these recommendations:

• While you scan, pause regularly and check for dust on the camera lenses and laser scanners.

• If required, clean them and the whole device.

Operating in high temperatures

Do not use the device when temperatures and humidity levels are outside the ranges defined in the Datasheet of the device. The temperature range is determined by the built-in components of the device, such as the cameras or PC. If exposed to excessive heat, the integrated cooling system will be overloaded and other components like the CPU will not operate correctly. This can ultimately lead to performance issues like lagging live SLAM or broken datasets.

Scanning in dark areas like a basement

Some projects need to be scanned in environments where there are dark areas - there is just not enough daylight or artificial light sources present. While the human eye can adapt to minimal light, your device is limited by technical constraints. What can you do to overcome these constraints?

Warning: Make sure when scanning in darkened areas to take appropriate precautions. Take care where steps and wet surfaces may not be obvious.

There are three options to choose from, when scanning dark areas:

• Scan the building as is - no extra light sources: With limited lighting, panoramas, point cloud coloring and VO will be impacted. Both are based on the pictures taken by the cameras during scanning. If no or only a very little quantity of photons reach the camera sensors, the results achieved are limited. If your project is not reliant on coloring, you can still scan, but the VO cameras will not be able to function adequately, and the SLAM will not be as stable as in a well-lit environment. When taking panoramas, stop for longer as the cameras will need longer exposure. We recommend skipping coloring of the point cloud during post-processing, which produces intensity values from the lidar measurements instead. You can achieve that by:

  • Cloud Processing: When processing data in the Cloud, you can deselect the point cloud coloring. You can find help on this in Point Cloud Settings.

  • Desktop Processing Software: When processing on a local Ubuntu workstation or server, use the additional flag in SiteMaker or Ubuntu terminal --no-color-cloud. You can find the options for that here in our documentation on Adding Custom Arguments.

• Add a light source to the device: This option is not recommended as it interferes with the sensors and invalidates the device’s warranty or subscription contract.

• Add additional lights to the environment: (Recommended). Additional light sources will be necessary for the full area covered in one scanning session. When planning the lighting follow these rules:

  • Place floodlights before starting to scan.

  • The floodlights must not be triggered by movement but be permanently on.

  • Do not carry the floodlights around within one scanning session.

If the guidance is not followed, the lighting changes will be visible both in the coloring (mix of bright and dark, because you captured the same area in both conditions) and the point cloud itself, due to the movements and changed objects. Overall, with limited light sources, the coloring of point cloud and panoramas will be much less than perfect.