Finding my drone in a tree with thermal imaging

[razorack]

Hi there,
I have spent a frustrating 3 days looking for my phantom 4 drone in a huge ash tree. Its about 30 meters tall and i cant for the life of me see the thing.
I was wondering whether anyone here would know whether a thermal imaging camera would detect the drone from the ground. Assuming that the drone is probably at the top of the tree, that would be around 30-40 meters away. The drone is our of battery now so i assume no real heat emanating from the motor, but i wondered about the difference between a plastic object and the tree structure in thermal properties.
Any advice greatly appreciated.

[metrologist]

binoculars?

[razorack]

Tried binoculars without success. As you can imagine there are a lot of layers of leaves

[metrologist]

do you have a decent camera? Take a couple photos and post them up. Someone has good eyes. Might also use photo editing SW to manipulate colors and shading.

[razorack]

Thanks for the suggestion, and i cpuld try that tomorrow. But getting back to my original idea, does anyone have any thoughts on the usefulness of a thermal imaging camera to locate the drone?

[SL4P]

I doubt you'll have much luck with thermal imaging - as the time elapsed will mean the drone is now at the same temp as the surroundings.

One possibility. If the batteries are still good to go, wait until late evening, when the tree and sky have cooled - then crank it up - motors actually running or not, the motors and electronics could emit a whisper of heat - and then you'll need a looong ladder.

[zapta]

Try to locate it with another driver flying above?

[Silveruser]

I'd give it try. Leaves reflect a lot of IR. If you've ever seen an IR photo, healthy leaves are a bright white. Your drone may not reflect as much but if it's hidden by the leaves well you might have to wait for fall.

[CatalinaWOW]

You probably can't see it in the IR any better than the visible.  Leaves are virtually opaque at all IR wavelengths.  Now if you could get your hands on an appropriate radar it might help.

IF there is a line of sight to your drone your best chances will be just after dawn and just after dusk.  The thermal time constant of your drone is undoubtedly much different than the leaves and smaller branches, so will appear most different at times of rapidly changing temperatures.

I suspect your best option is to find a tree surgeon friend or other expert at climbing trees to actually go up there and look.  There is some chance they can actually bring it down with them.  If you find it with IR you still have to solve the retrieval problem.

Finally, are you sure it is in the tree?  Any chance it crashed on the other side of the tree, or fell out after crashing, and has been picked up by kids or other passersby?

[Aodhan145]

Nobody asked the real question. Why were you flying so close to the tree?

[razorack]

Thanks for the Replies! The drone is stuck in a tree in a private property where no public walk. I was there trying to get footage for a wedding. I used an app called Litchi which has the ability to plan waypoint missions including altitude. I had done some run throughs previously and there was no problem with the drone clearing the trees in the run through rehearsal (i had line of sight then) . Unfortunately i didnt have line of sight during the wedding. The drone s app has the ability to broadcast the last known GPS position, which I have. After the crash the drone was still giving me live video feed ( i know its live because of the branches moving in the feed). It showed a whole lot of leaves, that are easy to identify as Ash tree leaves. Those leave correspond to the tree it is shown to be in with the GPS . So I am reasonably certain that I know which tree its in - and its a huge ash tree!
I thought about getting someone to fly over with their drone, but I am currently in france on holiday- so language is a problem!
I am reasonably sure the problem has occured due to an IMU calibration (these drones need to be magnetically recalibrated every so often) i hadnt been alerted to do this until after the accident! I have been told on a drone forum that the IMU doesnt affect the GPS ability, so the broadcast position is I assume accurate.

Thats the backgroundn  now getting back to the TI. I understand now, that during the day , the drone is unlikely to be seen , and that i need to wait until temps are changing rapidly. But a question- wouldnt the plastic of the drone heat up differently to the leaves ? (much thinner and less thermal mass) If so wouldnt there be a possibility that it could be seen during the day ?
As I was considering buying a Flir one or similar , I was wondering how effective it would be , given the distance away. What is the range of the flir one? Would I likely not have enough detail to distinguish where the drone is (assuming it shows as a different thermal) Any other considerations. Thanks

[ivaylo]

Nobody asked the real question. Why were you flying so close to the tree?

Yup, I have no real sympathy either. It's the age of adults (I assume the OP is an adult) have children's problems - "sir, can you take my kite down?" Everybody is a "drone operator", "content producer", you name it...

[Ian.M]

A combination of visible light and near-IR photography can detect foliage damage, by the change in the ratio of near-IR and green reflectance.  If you can get a drone with  high resolution near-IR (*NOT* thermal IR) and visible light cameras to fly your route approaching the tree at a greater altitude within the next day or two, you *MAY* get lucky and be able to determine the impact site from the foliage damage.

As your drone is almost certainly well embedded in the canopy, it is unlikely to be sufficiently exposed to direct sunlight for  there to be enough temperature differential for thermal IR imaging to be of any use.  Also affordable Thermal IR is generally relatively low resolution, so at best, you'd see the drone as a low contrast blob that wont be easy to distinguish when partially obscured by a lattice of branches with more branches in the background.

[Fraser]

IMHO a TIC is not the best way forward in this particular scenario as you are unlikely to have clear line of sight.

Ask yourself this question..... what would you do to recover the drone if you can see it at a height of 30m from the ground ? That is lethal fall altitude so you would be either very brave or silly to attempt a free climb to retrieve it.

The best approach is to either approach your local climbing club or a professional tree surgeon and ask what they would want to charge to recover your drone. These people know how to climb safely and have the best chance of success. When model aircraft, submarines or boats sink in lakes, the local diving club rescue them for a small fee as practice and a little adventure 

Just my thoughts on the matter

Fraser

[jpanhalt]

1) A view from above is often helpful.   When we have lost models in corn fields, friendly local flyers will sometimes help locate them.   The use of a second drone may help, but a real human observer would be better.

2) Wait for the leaves to fall.

3) Hire a bucket truck.  Trucks that go to 20m are common in the US.   You may not need to get to the very top of the tree.

4) Among airplane modelers, it is well accepted that most of the damage in recovering from trees results from the recovery efforts, not from the initial impact.   That is where a bucket truck will be of great help.

John

[Refrigerator]

Climb the tree. 

[razorack]

Nobody asked the real question. Why were you flying so close to the tree?

Yup, I have no real sympathy either. It's the age of adults (I assume the OP is an adult) have children's problems - "sir, can you take my kite down?" Everybody is a "drone operator", "content producer", you name it...

Such an unnecessary comment. I explained in the previous post what had happened. did you not read it - or did its meaning escape you?

[razorack]

A combination of visible light and near-IR photography can detect foliage damage, by the change in the ratio of near-IR and green reflectance.  If you can get a drone with  high resolution near-IR (*NOT* thermal IR) and visible light cameras to fly your route approaching the tree at a greater altitude within the next day or two, you *MAY* get lucky and be able to determine the impact site from the foliage damage.

As your drone is almost certainly well embedded in the canopy, it is unlikely to be sufficiently exposed to direct sunlight for  there to be enough temperature differential for thermal IR imaging to be of any use.  Also affordable Thermal IR is generally relatively low resolution, so at best, you'd see the drone as a low contrast blob that wont be easy to distinguish when partially obscured by a lattice of branches with more branches in the background.

thanks Ian - thats the sort of useful info I was asking for

[ivaylo]

Nobody asked the real question. Why were you flying so close to the tree?

Yup, I have no real sympathy either. It's the age of adults (I assume the OP is an adult) have children's problems - "sir, can you take my kite down?" Everybody is a "drone operator", "content producer", you name it...

Such an unnecessary comment. I explained in the previous post what had happened. did you not read it - or did its meaning escape you?

Yup, unnecessary comment to an unnecessary question. Did you really join an electronics forum just to ask this?

[Fraser]

The OP seems hell bent on imaging the Drone rather than considering how best to recover it. All a bit weird IMHO. He received good advice on finding and recovery but has locked on to trying to image it as the answer he wanted. Oh well, I hope all goes well for him and he gets his Drone back. One thing is for sure, recovery will not be cheap.

[madalf71]

If you can get access, and depending on height, Bucket truck, not heard them called that before...... Cherry picker or mast boom lifter here in AU.

Re FLIR Have to agree with previous comment, leaves will hide it from the FLIR. And even if you locate it, you'll most likely need the above option to get it down anyway.

Good luck.

[Ian.M]

There is no point in paying more for retrieval than the value of the drone and camera.  The costs of hiring a bucket truck/cherry picker are likely to be quite high, and  there may well be access problems, especially if its an unimproved ground surface and on a slope.  If it can be located, then the suggestion to hire a tree surgeon to attempt retrieval, is probably the most practical.   Worst case it may have to be pushed out of the canopy with a long pole and caught in a stretched net held by assistants on the ground.  Even if there is significant damage to the shell and/or gimbal mount its still going to be worth retrieving if costs can be kept down.

[zapta]

And then there is this drone recovery method

http://youtu.be/bIif4c0L-60

[Ian.M]

Guy's a dangerous idiot.  No PPE, didn't cut a directional notch, and felled it in a direction that ended with the drone under the tree!

[CatalinaWOW]

Guy's a dangerous idiot.  No PPE, didn't cut a directional notch, and felled it in a direction that ended with the drone under the tree!

You forgot to mention a dull saw.  Should have been through a tree of that diameter in much less time.

Can't really fault the direction relative to his drone.  The video never showed recovery, and there is no good reason to suppose the drone didn't come loose and follow gravity to the bottom when the tree hit the ground. 

[Simon]

what an asshole, judging by the ground it was not his back garden and not his tree to cut down. Some places are just full of jerks.

[Refrigerator]

what an asshole, judging by the ground it was not his back garden and not his tree to cut down. Some places are just full of jerks.

It could be his property nonetheless. Although that does not explain his behaviour, looks like he spent more time playing than cutting.
But that doesn't surprise me, i just saw an american say that france is in england, the guy also happens to call himself an "inventor". 
As long as it's not my money going down the drain i'm ok with what they're doing.

[TerraHertz]

Even if you can locate it, is there any practical way of retrieving it?
I'd suggest you or someone with appropriate equipment simply climb the tree, to get a view from near the canopy.
Would the property owners allow any damage to the tree? Hiring large machinery that could reach it from outside the tree would probably exceed the cost of the drone.

Maybe just let it go? Or....
youtube.com/  watch?v=8_Bo2ro60ro

[Simon]

Talk about letting go, why drag this up over a month since the last post ?