How can i detect an object's distance from the Tello drone's camera?

RogueSquadron1 · Dec 31, 2019

It seems this is not supported in both of the Tello models.
But i'm hoping this is directly supported by a more advanced drone (such as Mavic).
Else I'd have to go straight into image recognition algorithms to try to obtain this information.

Anybody ever tried to do something like this?

TelloCarl · Jan 1, 2020

You can't, the closest thing you could do is get really close and then measure using a virtual GPS as you fly backwards from the object. The Tello is just not designed with collision detection.

volate!lo · Jan 1, 2020

You can't, at least not from a static image. No stereoscopic view - no distance.

Now if the drone moves and you know the distances it travels, you can derive distance from this information and several images. Never done that but doesn't sound easy to me.

pgminin · Jan 3, 2020

You can estimate the distance of an object from its apparent angular size (in pixel), its real size (in cm) and the trigonometric tangent function.
I do this quite well in my computer vision based 3d person tracking

volate!lo · Jan 3, 2020

pgminin said:
You can estimate the distance of an object from its apparent angular size (in pixel), its real size (in cm) and the trigonometric tangent function.
I do this quite well in my computer vision based 3d person tracking

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thats cheating because you know your own height. but smart..

Cool stuff by the way. At 2:14 you are identified as a sheep on a dike

pgminin · Jan 3, 2020

volate!lo said:
thats cheating because you know your own height. but smart..

Cool stuff by the way. At 2:14 you are identif

In some conditions (grass background, white shirt, drone quite distant) , my object detector confuses me with a sheep (fortunately.with a low confidence!) and It stops the drone, A quick workaround would be to allow sheep tracking ... Not the best if someday someone encounters a flock!

volate!lo · Jan 4, 2020

pgminin said:
In some conditions (grass background, white shirt, drone quite distant) , my object detector confuses me with a sheep (fortunately.with a low confidence!) and It stops the drone, A quick workaround would be to allow sheep tracking ... Not the best if someday someone encounters a flock!

Could be a new application: TelloShepherd - Circles the baricenter of all sheep in view to make them flock together.

pgminin · Jan 4, 2020

volate!lo said:
Could be a new application: TelloShepherd - Circles the baricenter of all sheep in view to make them flock together.

Great idea, definetly a killer app for the modern Shepherd!

The most complex computer application I've done untill now is for basketball video recording, we are not very young so maybe slower than sheep... and this makes things easier!

Maybe you have seen it somewhere but I link here again anyway ....

volate!lo · Jan 4, 2020

pgminin said:
Great idea, definetly a killer app for the modern Shepherd!
The most complex computer application I've done untill now is for basketball video recording, we are not very young so maybe slower than sheep... and this makes things easier!
Maybe you have seen it somewhere but I link here again anyway ....

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no worries I looked at all your videos. As you may have seen I am working on a CV-based followme app so I use all input I can find.
But I am still fighting the PIDs - and apple as they won't allow me to release the app for imaginary legal reasons... ?

pgminin · Jan 4, 2020

With a control engineering background I followed a model based design (MATLAB + Simulink) to model and design pid control loops. If you want some insight about my solutions (or whatever Is your fighti I can give you with pleasure maybe by mail.
On the other hand trying to port this on Android for me is quite a nightmare.
For now I'm not trying to sell an app, but going in the field with a smartphone Is really really better (for notebook size/weight and safety reason)
I let aside Apple world ...

volate!lo · Jan 4, 2020

just the PID fine tuning. It works OK, but sometimes there are situations where Tello just doesn't react quickly enough even though it could with some better tuning.

Not a big deal- just some trial and error. But the weather doesn't cooperate here

pgminin · Jan 4, 2020

Nice! In tello sdk there Is a speed deadzone between -10 and +10 command values. This nonlinearity Is annoying when the proportional error Is low ... I don't know if this can help you ...

volate!lo · Jan 4, 2020

Yep that's it. Proportional is low, integral starts to build and then it overshoots. I guess I will just define a dead zone for yaw.

pgminin · Jan 4, 2020

After many trials I solved adding/subtracting a constant. Something like +8*sign(err_prop) to reduce this deadzone!

volate!lo · Jan 4, 2020

Thats what I planned to do, but for each of the 3 PID components individually.

However the refused admittance to the Apple store has brought this project to a complete stop while in the middle of this PID tuning wrestle. No point to continue until I get approval