What is a Laser Scanner?
From our video above:
The term Laser Scan has become synonymous with surveying over the last 10 -20 years. People now often ask for a ‘scan survey’ or actually just assume that a ‘survey’ is a laser scan. But a scanner is a very specific tool that creates a particular form of data. They are used to collect a lot of as-built data very quickly.
360 Degree Data Capture
The scanner has a central aperture, which is where the laser is emitted from, and this aperture rotates very fast. At the same time the entire scanner rotates around on its base. This means the laser emitted in a 360 degree arc and everything the scanner can see from its location is collected as point cloud data. Normally these scanners are capturing millions of points of data per second, each with its’ own XYZ coordinate.
The Scanner Can’t See Through Things.
Note though, the scanner can’t see through things, it can’t see through the wall or round the corner, it can’t see through tables and chairs, it cant see through a crane or scaffolding structure or through a pipe rack. So to capture the full area the scanner needs to be moved multiple times to pick up various individual scans that when all joined together in processing, create one big point cloud of the target environment.
1 to 5 Minutes per Scan
You will often hear terms like Reality Capture or Scan to BIM associated with laser scanning, but at its most basic it is a method for capturing a lot of as-built data very quickly. There is a lot of variation depending on the equipment and settings being used but broadly speaking imagine each scan usually takes between 1 – 5 minutes so you can cover large areas very quickly.
Technology from: Leica, Trimble, GeoSLAM
A couple of notes on laser scanner tech. What we have spoken about is ‘Tripod based laser scanners’. But technology is always moving on, there are now technologies such as mobile laser scanners, mounted to the back of cars, on back packs, on rail trollies, and hand held mobile laser scanners – devices like the Leica Pegasus, the Trimble MX9, the GeoSLAM Zeb Horizon – each comes with its own unique benefits and limitations.
Use the Right Tool for the Job at Hand
In terms of precision and accuracy, tripod based is usually king, however for many situations a mobile scanning option may be the perfect tool for the job. It is all about using the right tool for the job at hand. It is also worth noting that drones, high resolution cameras and software like Pix4D can also create point cloud data, without necessarily using laser scanners themselves, although that is something we will talk about another time.
That’s a brief intro to laser scanners, we will be talking more about what point cloud is and then touching a little on BIM at another time, but for now you can like and subscribe to follow our channels, please get in touch or leave a comment if you have any questions and catch you all next time.
See our 3D laser scanning related case studies here.
For more information you can get in touch with Operations Director, Clif Webb