Hi dear community,
I am currently working on a project where I want to generate a 3D reconstructed model consisting of rubble piles (in consequence of a building collapse) via remote sensing. In my case, I employ LiDAR aerial laser scanner as well as aerial photogrammetry for point cloud generation of the disaster scene. The problem is that solely the surface of the scene that lies in the field of view can be reconstructed. However, in order to evaluate the structural behavior of the debris with regards to structural stability, I need to know how the collapsed elements are structured beneath the debris surface. Does somebody has an idea how I can proceed or has anybody conducted a related study? Is my objective even feasible?
Thank you in advance!
Hi Amar,
As far as I know, your objective is not feasible to attain using solely aerial lidar and photogrammetry. Photogrammetry as a passive remote sensing technique, only gives you what the camera can "see" i.e. the surface of the object. Lidar is known to be able to penetrate some surfaces (usually vegetation/trees), but I doubt that the laser waves can penetrate hard surfaces like building rubble...
I would say that the solution would be to augment your data with terrestrial sensors (e.g. TLS and/or close range photogrammetry either terrestrial or using a drone).
However, if other people has performed any experiments using other methods, I am also interested to know about it.
Best of luck,
arnadi
Hi Arnadi,
Thanks for the reply! I also doubt that LiDAR is able to penetrate building material, such as reinforced concrete or steel. Therefore, I was thinking of using Synthetic Aperature Radar (SAR). SAR sensor should be able to penetrate hard surfaces up to a certain distance. I'll try it and then I will let you know how it worked out.
You suggested TLS or close range photogrammetry. Can these techniques remedy the problem of capturing data beneath the surface? What if the LiDAR data is aqcuired through a low altitude flight of the UAV?
Best,
Amar
Hi Amar,
SAR may be useful but unfortunately I don't have enough experience in radar to say anything about it :( other people in ResearchGate may be more experienced on the use of SAR.
I'm not sure even low-altitude UAV lidar can penetrate hard surfaces, but a close-range UAV photogrammetry combined with terrestrial photogrammetry and/or TLS can certainly help you to get what you want provided that the project is properly georeferenced (to facilitate point cloud integration further down the pipeline). However, this would of course increase your field work budget, and I guess that's something to think about too...
Depending on the condition of the rubble, oblique photogrammetry may also be useful. But still, it will only give you what the cameras "see".
best,
arnadi
Dear Amir,
I have worked with ground-based Lidar and with terrestrial GPR (Ground Penetrating Radar). Lidar can not penetrate a solid rubble pile and GPR does not work well on rubble, especially if the surface is irregular...
Respectfully yours, Joel
J
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