I’m using drone-mounted cameras to get video of sites where people slip and fall and buildings fail. The evidence is different, easy to get and cost effective – a few hundred dollars depending on location. See Examples below also the References.
I take video almost exclusively because the resolution is so great in frame grabs that stills are not necessary. Video is normally shot at 30 frames per second. You can fly as fast or slow as you like, dip up and down, slip sideways and hover – videoing all the time. Altitude and speed are recorded, and GPS on some drones.
There’s nothing technical about this. You can get video with a simple, inexpensive camera fixed to a drone flying a few feet, 10s of feet or 100s of feet above and all around the site of an accident or failure. The first aerial video I had taken was with a GoPro camera like those attached to a skier’s helmet for a scary run down a mountain.
Video from aloft is not the only means by which evidence is collected during a forensic engineering investigation. This way, however, is relatively new, simple, cost effective and the evidence is from a different angle and sometimes quite revealing. A DVD of the video on everyone’s laptop also enhances conference calls.
Following are some ways I’ve used video taken from a drone in recent years, or might have, and ways I may do in the future:
Example #1 Recently.What better way to survey and record defects in a high retaining wall involved in a flooding problem than from a few 10s of feet above the ground and off the face of the wall?
Example #2 Or identifying the potential location of fuel oil spilled on different properties as evident from distressed vegetation and colour changes in the ground so visible in a video taken from a few 10s of feet up?
Example #3 A choice application would have been capturing the re-enactment of a nail gun accident on video from a few feet and right over the scene. Unfortunately, there was no room for a drone to hover in the tiny room that was available – the actual scene was more expensive.
Example #4 My forensic investigation and re-enactment a few years ago of the John Morris Rankin accident at a test site at the Shearwater Airport would have been a perfect application of aerial video as would filming the 75 foot cliff John drove over in Cape Breton. As it was, I got good aerial video of the test site from a Sea King helicopter borrowed for the purpose. I also got footage from the top of a rented boom truck. Today I would use a drone fitted with a video camera.
Example #5 Quite recently I thought to use a drone to get video at a step-down and stumble accident site where there was lots of room to hover.
Example #6 Even more recently I’ve thought of using a drone to video the re-enactment of slip, trip and fall accidents in public places where I know there is lots of room to hover. Places like auditoriums, sport’s facilities and airport terminals.
You can grab frames at 1/30 second intervals from a video of a re-enactment and study slight changes in the movement of the slip and fall victim.
Techniques like these are being used now to estimate the speed of cars and airplanes in accidents. Resolution is so good that you would be able to see the nail in a nail gun accident from 200 feet up – if there was an airport terminal with a ceiling that high.
There is also some chance that study of the condition of the floors as seen in the videos – subtle changes in pattern, colour, texture, material or workmanship that contribute to floor skid resistance, – would cast light on the cause of the accidents.
This is like terrain analysis in civil engineering, – a well developed method – except indoors rather than outside. The terrain is a floor rather than the ground downhill of a fuel oil spill or along the proposed alignment of a highway.
Example #7 Also extremely valuable – surveying damage to the side of a multi-story building with a drone-mounted video camera – the former provincial land surveyor in me is enthused about this one.
Video could be taken from a distance of a few 10s of feet to document the character and extent of the damage to the wall, then from a few 10s of inches to measure the damage. No expensive scaffolding necessary and workers climbing up and down.
Scale for measuring what is seen in the video would be got from the known size of building components used to construct the wall. For example, the known size of a concrete block and the known thickness of the grout between concrete blocks
The character and configuration of the wall damage, and the size of cracks often points to the cause of the damage. Random hairline cracks due to normal material shrinkage? No worries. Cracks that exhibit a predictable configuration and need to be grouted tell quite another story. The cause is often almost a given, and would be one of the ways buildings fail.
Studies of how buildings fail have identified at least 209 different ways and they’ve all got causes. (Ref. 3) And these don’t include all those involving the foundations and foundation soils – too often the Achilles’ heel of designers and builders.
This method – taking aerial video with drone-mounted cameras – is being used now in North America. (It’s a new application of photogrammetry – the identification and measuring of the size of things on the earth as seen in photographs taken from the air)
Using video shot from a drone has got to be one of the most cost effective forensic engineering methods to develop in a long time. Getting a lot of data quickly and cheaply is not too hard to take.
Like I said above, the savings continue when you distribute a DVD of the video to the parties involved for a conference Zoom call while each party views the scene on their laptop or device of choice. I did this during one forensic investigation and surprisingly got more data still from comments made during our discussion.
With today’s technology, you can even “crew” on a drone flight as “navigator” by standing next to the “pilot” flying the drone and direct the video to shoot from a remote display. The video takes on more meaning when you’re part of the action. I also end all my videos with footage of the pilot and myself, sometimes the plaintiff, standing on the site so there’s no question we were there.
- A picture’s worth a 1000 words, possibly many 1000s in forensic engineering with a new aerial photographic technique. Posted January 15, 2014 (see aerial photographs from a drone flight in this blog)
- New forensic aerial photographic method proving extremely valuable. Posted January 30, 2014
- How many ways can a building fail, and possibly result in civil litigation or an insurance claim? Posted July 10, 2014
- Forensic photography – the expertise available in eastern Canada. Posted February 26, 2015
- Fixed wing drones – another tool in forensic engineering investigation. Posted November 4, 2015
- “Crewing” on a forensic drone flight. Posted October 4, 2016
- Getting evidence with a low cost, low tech drone flight over a forensic site. Posted March 31, 2017
- Conference call on a “drone flight” reduces cost of civil litigation. Posted May 18, 2017
- “Unexpected” evidence and the importance of drone photography in forensic investigation. Posted July 19, 2017
- Drone video as a forensic technique is joined by drone photography as an art form. Posted August 2, 2017
(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. August 9, 2018 firstname.lastname@example.org)