3D Floor Scanning – Is it Really Suitable?

At Face Consultants Ltd we always push the boundaries of 3D scanning for measuring floors for all specifications, from traditional Free Movement specifications to complex specifications for robotics systems. We strive to be the first to deliver laser-scanning surveys that tick all the boxes.

As part of these efforts, we are constantly testing different scanners and processes to find both the positives and negatives. Within this paper is a study carried out comparing one 3D scan to another whilst maintaining the same parameters between each scan on a large test area. The results are quite surprising!

Setting the Parameters for a 3D Laser Scan Comparison

1. For the test we used an area of floor approximately 2500m², cleaned with a scrubber dryer before each scan to ensure that no debris would affect the results.
2. The scans were carried out over 2 days using the same devices, setup, and surveyor, (methodology for the scans are described below).
3. Scan A (left on the below diagram) was the initial scan on day 1 and Scan B (right on the below diagram) was carried out the following day.

On these scans, the red indicates a height of 40mm and the blue a low of 9mm.

Small 3D Scanning Differences Have a Large Impact

Although Scan A and Scan B look to be similar in appearance initially, when you look in detail, the differences between the two start to become apparent.

The diagram in the middle shows the difference between the two scans, with the red sections indicating differences up to +1.7mm, and the blue up to -3.5mm!

Although these differences may seem small, the article HERE describes how even a 0.5mm error can make a huge difference to the results.

Individual 3D Scan Discrepancies

When looking at the comparison plan in the middle, there appear to be distinct circles formed as the colour scale is reduced. These can also be known as “crop circles”. Although they may look a bit alien, they are not from another world but are indicators of the discrepancies in the individual scans. Read more about the anomaly of scanning crop circles HERE.

Is 3D Floor Scanning Suitable?

At this time, from the trials Face Consultants have carried out, due to the inaccuracies and lack of repeatability the use of 3D scanning is still not suitable for measuring floor profiles for compliance with surface regularity standards within the logistics industry.

We are hopeful that this will change as the developments into the hardware and processes continue and we will continue to strive to be the first company to deliver a 3D scanned floor survey to the accuracy required.

Until such a time as we can confidently and accurately provide 3D scans, we supplement all using the latest digital floor flatness testing equipment, designed, and manufactured at our UK headquarters.

Should you have any inquiries or wish to delve deeper into the subject, please don’t hesitate to contact us today.

Survey Methodology

Scanning was carried out on an area of floor approximately 160m x 16m, using a Leica P40 and a 1” Leica TS16 total station for control. Scans had 10m centres vertically, and 8m horizontally, resulting in 32 scans across the survey area.

The total station was set up within the survey area using 4 targets to resection from an already established control network within the building. From these setups targets for the scanning process were measured. This was done using Leica round prisms on magnetic mounts that were then swapped out for 4.5” Black & white scan Targets.

Targets were placed on every other pair of columns along the surveyed area, approximately every 16m. Scan targets were recorded by the P40 in the first 4 scans, scans 14-17, and the last 4 scans. All other scans were carried out without recording targets onsite but with targets visible for use in processing.

All scans were carried out using the 3.1mm @ 10m resolution with normal sensitivity on the P40, where it took around 5 hours to complete the 2500m² area.

The same area of the floor was scanned twice over 2 days by the same survey team using the same kit and method. This was done to limit the number of variables between surveys so that the repeatability of the kit & process could be assessed.

Each day’s scan data was registered and unified using Leica Cyclone. Unified clouds were then cut down to remove everything but the required floor area.

N4ce was then used to extract a level grid from the clouds and create the elevation maps and comparisons seen in the example.

James Dare

James Dare is a Flooring Consultant at Face Consultants Ltd. He has over 15 years experience in the industrial concrete flooring industry involving designing, specifying, testing, constructing and rectifying high tolerance floors for the logistics industry.

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