How to use laser scanning spheres

ProGEO Team
Dec 9
2 min read

When it comes to 3D laser scanning, precision is everything. Whether you’re surveying a construction site, mapping a building interior, or capturing complex industrial structures, laser scanning spheres play a vital role in ensuring your scans are accurate and reliable. These reflective, easy-to-detect spheres, many equipped with handy magnets, act as reference points that help surveyors align multiple scans, register point clouds, and connect their data to real-world coordinates. In short, they’re small tools with a big impact on your survey workflow. We explain how to use laser scanning spheres as part of your surveying kit.

1. Purpose of Laser Scanning Spheres in Surveying

Surveyors often need to scan large areas, like construction sites, buildings, or topography. Scanning from multiple positions creates multiple point clouds, which must be aligned accurately.

Spheres help with:

Scan registration: Aligning multiple scans into a single coordinate system.
Georeferencing: Linking the scans to survey control points or known coordinates.
Accuracy checks: Ensuring the scanner’s measurements are precise across the site.

Spheres work better than flat targets in complex or cluttered environments because their geometric centre is easy to detect automatically.

2. Characteristics of Survey Spheres

Feature	Typical Specs / Notes
Size	Usually 50–150 mm in diameter. Larger spheres are easier to detect from a distance.
Material / Finish	Impact-resistant plastic with a matt finish to ensure optimal reflection
Mounting	Can be placed on tripods, stands, walls, or poles. Stability is key for accurate detection.
Detection	Can be placed on tripods, stands, walls, or poles. Magnets, allowing them to attach securely to metal surfaces, are very useful for temporary placement on beams, pipes, or steel structures.
Placement	Spread evenly across the survey area. Typically, each sphere should be visible from at least two or more scan positions.

3. How Spheres Are Used in Practice

Set up spheres around the survey area
- Place spheres on tripods, stands, or directly on metal surfaces using magnets.
- Ensure they are visible from multiple scan positions.
Perform multiple scans
- The scanner captures the spheres as part of the point cloud.
Automatic sphere detection in software
- Software (e.g.,FARO SCENE software) identifies the centre of each sphere.
- The centres are used to register or align all scans.
Scan alignment/registration
- Matching the same spheres across scans allows the software to merge multiple point clouds into a single accurate 3D model.
Optional georeferencing
- If sphere positions are tied to known survey coordinates, the entire point cloud can be referenced to a real-world coordinate system

4. Advantages for Surveyors

High accuracy: Sphere centres are easy to detect precisely.
Reduced human error: Automatic detection reduces manual alignment work.
Flexible placement: Works in cluttered or uneven sites.
Faster workflow: Faster registration compared to using flat targets or natural features.

5. Practical Tips

Use tripods with tripod stands or fixed mounts to prevent movement.
Place spheres at varying heights for better detection in obstructed areas.
Make sure spheres aren’t in direct sunlight, which can create scanning noise.
Combine with reflective tape on edges or corners if you need additional control points for complex sites.