Recording Cultural Heritage objects using terrestrial laserscanning becomes more and more popular over the last years. Since terrestrial Laserscanning System (TLS) Manufacturers have strongly increased the amount and speed of data captured with a single scan at each system upgrade and cutting down system costs the use of TLS Systems for recording cultural heritage is an option for recording worth to think about beside traditional methods like Photogrammetric. TLS Systems can be a great tool for capturing complex cultural heritage object within a short amount of time beside the traditional methods but can be a nightmare to handle for further process if not used right while capturing.
Furthermore TLS Systems still have to be recognized as survey equipment, even though some of the manufactures promote them as everyday tool. They have to be used in an intelligent way having in mind the clients and the individual cultural objects needs. Thus the efficient way to use TLS Systems for data recording becomes a relevant topic to deal with the huge Amount of data the Systems collect while recording.
Already small projects can turn into huge Pointcloud Datasets that End user, like Architects or Archaeologist neither can’t deal with as their technical equipment doesn’t fit the requirements of the Dataset nor do they have the software tools to use the Data as the current software tools still are high prized. Even the necessary interpretation of the Dataset can be a tough task if the people who have to work on with the Pointcloud aren't educated right in order to understand TLS and the results it creates
The use of TLS Systems has to have in mind the project requirements of the individual Heritage Object, like the required accuracy, standards for Levels of Details (e.g. “Empfehlungen für die Baudokumentation, Günther Eckstein, Germany), the required kind of Deliverables (Visualization, 2D Drawings, True Deformation Drawings, 3D Models, BIM or 4D – Animations) as well as the Projects budget, restrictions and special conditions of the object. And if it’s used in the right way TLS will fulfil all request and furthermore create additional recording, deliverable and financial benefit.
Christofori und Partner is working with TLS Systems on cultural heritage Objects since 2005 trying to optimize the use of these systems (even in combining different systems like TLS, photogrammetric or new techniques) as well as creating useable deliverables for the Clients (Owner, Conservator, Designers and the Public) they can work on with.
Data Capturing using TLS - General Remark
TLS Measuring Systems have improved enormous over the last 5 years. The Manufacturer increased the Speed of capture, Density of Capture and Accuracy of a single Pointcloud the Scanner Systems create when using it. Beside the system sizes and system weights decreased while – on first glance – the application and use of the system got much easier.
This made the systems interesting for various groups of professions beside Surveyors - who started working with the Systems at the beginning – like Architects and Archaeologist. And last but not least – also on first glance – the Costs for implementing TLS to the companies cut down with general system prices decreasing.
Some of the manufacturers even started promoting terrestrial Laserscanning as an everyday tool that anyone can use like a digital still camera on any kind of object.
“Just click the button and a nice Pointcloud will appear within a short time…” In reality it isn’t that easy!
Capturing a still image with a digital still camera is more than just pressing the trigger when you want to get decent information from the image – beside some overall color information. You need to take in mind image section you need to focus on, setup the tripod correctly, light situation, object shadowing, control aperture, focal distance, etc. before you will capture an image that is worth to be taken for further use in applying it to the documentation of an heritage object.
With terrestrial 3D Laserscanning systems it’s the same. The application of terrestrial 3D Laserscanning is much more - if you want to get more than just a “Pretty Image“ out of it.
0TLS Systems still have to be regarded as Survey Equipment that have to be used having survey standards, setups and workflows in mind as well as the individual Object and its surrounding and the purpose the Laserscan is made for!