Get some real answers about mobile scanning accuracy

[gpavlidisNavVis]

Hello laser scanning profs,

NavVis recently published a guide to evaluating the accuracy of an indoor mobile scanner and I thought that this would be of interest to you folks.
Have a look here: https://www.navvis.com/accuracy-handbook
The independent metrics to verify the accuracy of mobile scanning can be applied to any SLAM based mobile scanner of your choice (and yes nowadays there are many out there).

So next time you are considering an indoor mobile scanner, check the accuracy specs and how they are defined .

[Least]

Pretty interesting, but would like to have seen the height differences between the three methods of all the targets stated.

[GPavlidis]

Thanks for pointing that out. We 'll consider this in the next revision of the guide.

In the current version of the guide, the distribution and the height of the targets were arbitrary selected in order to account for all possible factors influencing the measurements.

Just one question to make sure that I understand your point correctly, why do you consider the height differences of the targets important?

[Least]

You are evaluating the accuracy of your mobile scanner, you have surveyed the same floor plan with your scanner, a total station and a static scanner.
You have evalauted the distances in plan but nothing in vertical, a full measured building survey would state levels to the slab, the ceiling, beam soffits etc.

[smacl]

Interesting guide. It would be useful if you also published all the data (mobile point clouds, static point clouds, and total station data) on which this was based.

[GPavlidis]

You are evaluating the accuracy of your mobile scanner, you have surveyed the same floor plan with your scanner, a total station and a static scanner.
You have evalauted the distances in plan but nothing in vertical, a full measured building survey would state levels to the slab, the ceiling, beam soffits etc.

Thanks for clarifying that.

Indeed for the comparison between mobile and terrestrial laser scanner, an XY plane was considered and in the next version, we might want to include the comparison in XZ and YZ plane as well for the reasons that you mentioned. (Inside information : Comparisons in XZ and YZ plane have been done internally and the only thing that I can say is that results look promising and similar to the one in XY plane)
Nonetheless, in the current version for the comparison between mobile laser scanner and total station, we already include distances both in plan and vertical. Specifically, the euclidean distance (vector) between the targets was considered and therefore any error in Z coordinate (vertically) was included in the final results.

[LorenzLachauer]

Finally we have been able to come up with a second document on mobile mapping accuracy, building upon the first document discussed above. In this new document, we focus on the accuracy of the NavVis VLX device. We tested the device in three different scenarios, and we compared the VLX data against TLS point clouds and a 2D plan created with a total station. See the results here: https://www.navvis.com/resources/navvis ... y-handbook