Bridge Inspection

[IrishSights]

Peter, have you explored using close proximity photogrammetry for measurements? You would just need something of a known size or a scale in bar in the imagery as reference. Once you create a 3D mesh in, for example Photoscan Pro, you can measure. Using Meshlab too it is easy to measure point to point. Maybe your required measurement is to small for this method, I don't know. I have done quite close measurements using this method on archaeological sites from ground imagery and aerial but measuring mm size fractures might be difficult. I suppose it would depend on how close you were. You looked pretty close in your video though!

 

[Peter Syson]

Dear Irish Sights
Thank you for your suggestion. We already do survey using Pix 4d on a 3dr octo...so the question is can we use a mesh of photographs to measure from a copter in close proximity...? the size of the hairline fractures are down to 0.15mm!
Just of the top of my head!
The work flow is that you have an inspector next to you, watching and saying whether he/she wants a closer look and pics.
Video the outside surfaces, less time and easier to do a run, and generally more light. Also less data and the inspector can run through video easier.
For the underside...less light and environmental issues arise.
Don't video but just a visual for the inspector to look at.
Stop and photograph points of interest. Eg headstock and bearings.
Less data and this is what traditional process would be. Except they may physically measure at this point.

As to mesh?
On larger fractures I think you could....
The amount of data would be enormous, due to the number of potential faults, processing in Pix would be time consuming. However there are new programs coming out for 3d mapping for craft like the Phantom...no measurement though.
So at the moment the photographs highlight potential areas and the inspector can then determine whether a closer inspection is warranted. If so then they can break out the cantilevered arm, truck, traffic control etc.
As to the issue of lights, in Australia we have pretty good light! Most inspections do not need lights to see where we are going. Can use bike lights, but do need flash for camera to get best results. Watch the white out overexposure on concrete though. Hence a really bright light can be a pain, not enough light and you don't get the depth and contrast.
I say all this because we have a custom quad to do inspection, built for under $10k. Not a $50k off the shelf. When (and I say when) it goes in the drink less pain! Less insurance etc.
Cheers for now
Peter

 

[shaun666]

Because certain countries ban outright the mounting of a laser or projectile firing device of any kind to any form of RPAS.
Obviously, an individual needs to satisfy themselves (and the law) that they are acting in accordance with their local or national air laws when mounting anything that radiates or fires from their UAV.

After researching Lidar for UAV's I found that the laser used in Lidar equipment is (eye safe) so different to the laser pointer style. I cant remember the site I read it on but are similar to the units used in police speed guns.

 

[gunford]

Is anyone working on an app that would use the sensors on a P4 or guidance on Matrice 100 to scan bridges or buildings. With the guidance and a camera on the top of the M100 you could scan underneath as well.

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