What is Laser Scanning & 3D Surveying?

‘Laser Scanning’ & ‘3D Surveying’ read as though they’re from an Isaac Asimov novel, and tend to invoke images similar to those seen in the film Prometheus, of a floating ball firing lasers in all directions.

Although technology isn’t quite there yet, I think those who aren’t already familiar with the discipline might be surprised to know how close imagination is to reality.

In very simple terms, the majority of today’s laser scanning instruments work similarly to a total station or a high end disto, in that they use a laser and some clever maths to judge distance, direction and elevation to identify a point in 3D space.

Where the laser scanner really takes the lead is in the sheer amount of points it can record in a relatively short time frame. This mass points allows for the creation of point clouds, where several individual scans are stitched together to create an accurate model of the scan target and it’s surroundings. These point clouds can (amongst other things) then be used to take measurements, generate renderings and create very high accuracy drawings.

So why would you want to use one?

The reasons (in my perhaps bias opinion) are extensive, but two key selling points are; if used correctly, these instruments capture the world in 3D accurately and effectively. It’s almost like bringing the site back to the office with you, almost.

Here are just a few things I use ours for:

  • Floor plans
  • Elevations
  • Sections
  • Topographical surveys
  • Heritage Surveys
  • Fly-troughs
  • Visualisations

So…. sold on 3D Scanning yet? Wait a moment. As with anything, these instruments do have their drawbacks. The top four for me being; weather resistance, mirrors, range and cost.

Firstly, weather resistance, or lack thereof dependent on the model. Although it is definitely possible to conduct a laser survey in the rain, I would recommend waiting for the weather to clear up. As amongst other things, point data can become degraded, as the wet reflective surfaces can interfere with the laser.

Which brings us neatly on to mirrors. Laser scanners hate mirrors. As the measurement of each point is reliant on the accurate calculation of a laser beams flight, mirrors pose a bit of a challenge. As when the laser is reflected off a mirror, the instrument can return some very ‘interesting’ results. For example, I’ve seen large areas replicated ‘through’ a mirror and positioned several meters down the road, just because it wasn’t covered correctly.

Next, range. It’s a little ‘apples say hi to oranges’ and is completely dependent on the instrument. But as a rule of thumb, a scanner’s effective range will not match that of a total station’s. Particularly one in the same price bracket. For example, the X330 scanner from Faro boasts an extra-long range of 330m, but a FlexLine TS06plus total station from Leica at less than a quarter of the price can survey in excess of 1000m.

Finally, cost. Yes, I’m sure you’ve guessed it by now, these instruments aren’t cheap. For example, at the time of writing this article the previously mentioned X330 laser scanner from Faro would set you back over £41,000 (inc. VAT) and this doesn’t include all of the ancillary kit/software required to start scanning.

So, in conclusion. Laser scanning may not be a replacement for the more traditional measuring techniques and instruments in all situations, but it is an extremely effective way to measure at very accurate levels.

If you have any questions regarding this article, or have a project in mind that you think the Laser Scanning team at CLOCKWORKLIME.com could help you with. Please feel free to get in touch.

Thank you for taking the time to read this piece, but please note, this article has been written form experience and is in no way infallible. I would be happy to hear and learn from others experience if offered.

 

 

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