Hi forum,

I've been having successful tests shooting hyperlapse in day time, but last night I tried shooting the aurora borealis and the outcome is very unstable. It seems the drone is swirving left/right and I am wondering if there is anything I could try to do to fix this. Stabilizing the video in post didn't really work either, I suppose the material is too dark.

The settings were 2" shutter time, ISO 1600 and 800. It was pitch black except for the sky. I had it in course lock mode with a max speed of 0.4 km/h. The gimbal was calibrated the day before. I am wondering if it could be that the obstacle avoidance being active is what is causing the movement..? I didn't think to turn that off before starting the shoot.
I am using the DJI RC controller and both it and the drone have the latest firmware.

I've uploaded the video, the movement is clearly visible along the horizontal axis.


Appreciate any input! Thanks!

It cannot have been hard wind?

I get the same thing with my Air 2S occasionally. It is wind moving the drone around.

Ah, I completely forgot to mention that the wind conditions were perfect, not even 1 m/s. Thanks for asking

GeirB Posted at 9-5 08:08
Ah, I completely forgot to mention that the wind conditions were perfect, not even 1 m/s. Thanks for asking

What was the wind like at altitude?

Mobilehomer Posted at 9-5 09:07
What was the wind like at altitude?

Negligeble. I've done hyperlapses in much worse conditions that didn't turn out looking this.

Not sure if this helps or not but I have flown at night a lot and when it's dark I notice the mini drifts around a lot more than during the day. Obviously gps doesn't need light but I wonder if the low light causes the other sensors to get thrown off. I typically don't notice it much once at altitude but still notice it from time to time.

Anyway, just sharing my experience which isn't much. The mini 3 is my first real done.

I am guessing that it uses the compass to work out direction at night, while during the day it probably uses a combination of GPS and optics to maintain this.

My guess is that the lack of details in the video + the bad magnetic conditions could have been the cause.

Eveezy Posted at 9-5 15:07
Not sure if this helps or not but I have flown at night a lot and when it's dark I notice the mini drifts around a lot more than during the day. Obviously gps doesn't need light but I wonder if the low light causes the other sensors to get thrown off. I typically don't notice it much once at altitude but still notice it from time to time.

Anyway, just sharing my experience which isn't much. The mini 3 is my first real done.

Interesting that you have been experiencing the same thing in low light conditions. This makes me think it is indeed using its vision system to maintain course and not GPS + compass.
It's my first real drone too

i00 Posted at 9-5 15:52
I am guessing that it uses the compass to work out direction at night, while during the day it probably uses a combination of GPS and optics to maintain this.

You could be right, would be interesting to hear DJI comment on this.

Montfrooij Posted at 9-5 22:56
My guess is that the lack of details in the video + the bad magnetic conditions could have been the cause.

If it is using optics to keep a steady course I agree. I can't imagine that it is caused by magnetic conditions though.

GeirB Posted at 9-6 00:26
If it is using optics to keep a steady course I agree. I can't imagine that it is caused by magnetic conditions though.

Well, those Northern Lights show that there is stuff going on in the magnetic field. But it is just a guess.

Montfrooij Posted at 9-6 00:28
Well, those Northern Lights show that there is stuff going on in the magnetic field. But it is just a guess.

You are absolutely right about that, though the activity was medium/high that night. Never thought to check with a different compass to see if it was affected because the aurora absolutely can do that.

GeirB Posted at 9-6 00:42
You are absolutely right about that, though the activity was medium/high that night. Never thought to check with a different compass to see if it was affected because the aurora absolutely can do that.

Please tell my wife this (that I'm right )
How does the hyperlapse work during daytime conditions?

is this video straight out of the camera? i guess with such low contrast it's hard for the algorithm to stabilize the video in camera.
if you still have the original Photos i suggest editing them in resolve or premiere using a tracking point set on a feature of the horizon that's always visible and stabilize the tracking point. not gonna be easy tho with this footage

Montfrooij Posted at 9-6 00:45
Please tell my wife this (that I'm right  )
How does the hyperlapse work during daytime conditions?

Sure thing, where do I sign?
I've not done too many tests during daytime, but the one's I have done have been fine - only minor stability issues.

tazztone Posted at 9-6 02:12
is this video straight out of the camera? i guess with such low contrast it's hard for the algorithm to stabilize the video in camera.
if you still have the original Photos i suggest editing them in resolve or premiere using a tracking point set on a feature of the horizon that's always visible and stabilize the tracking point. not gonna be easy tho with this footage

Except for increasing the exposure in Premiere the video is straight out of the camera. The quality would be a lot better if I kept the RAW files and worked on them of course, but this was kind of a first test of doing hyperlapses of the northern lights.

I suspect it's an algorithm thing as well, but I don't know what sensors is using - GPS, compass, vision or a combo. I do wonder if anyone has experienced that obstacle avoidance has an effect on hyperlapses?

I'm not aware that I can do point tracking in Premiere, but I'll have a go in After Effects!

GeirB Posted at 9-6 06:46
Sure thing, where do I sign?
I've not done too many tests during daytime, but the one's I have done have been fine - only minor stability issues.

Hahahahahahaha.
Just here
My best guess is that the image is analyzed during flight. But it is a guess and since my Mini 2 does not have hyperlapse, I can't test myself (oh and I'm not allowed to fly outside of daylight times here in NL)

Couldn't you have stabilized it in Prem pro? I cannot believe that it managed to capture the stars as well as it did, wow!!

Montfrooij Posted at 9-6 07:05
Hahahahahahaha.
Just here  
My best guess is that the image is analyzed during flight. But it is a guess and since my Mini 2 does not have hyperlapse, I can't test myself (oh and I'm not allowed to fly outside of daylight times here in NL)

Oh, no - really? That's a bummer. Luckily there's no rule against that in Norway as long as you fly VLOS. In either case, at that location the only danger would be crashing into something I couldn't see

Bashy Posted at 9-6 07:07
Couldn't you have stabilized it in Prem pro? I cannot believe that it managed to capture the stars as well as it did, wow!!

I did try to stabilize on Premiere, but the warp stabilizer had no idea how to handle this footage, too dark I think.

But yes, agreed! It's incredible what this little thing is capable of! Attached a photo from the same location, quick and roughly processed RAW image. I look forward to the next opportunity to capture a similar scene while keeping the raw files so I can pull out a lot more detail - I think that could look absolutely awesome!

GeirB Posted at 9-6 07:47
Oh, no - really? That's a bummer. Luckily there's no rule against that in Norway as long as you fly VLOS. In either case, at that location the only danger would be crashing into something I couldn't see

We have quite a few extra rules here in NL.
I do hope they will abandon that night limitation, as it can give really nice footage.

Hello there GeirB. I am sorry for the trouble this has caused and thank you for reaching out. May we please know if you have received any error message or error codes on the DJI Fly application when this happened and just a friendly reminder that DJI do not recommend flying your DJI drone during low light condition as the vision sensors may not work properly. Thank you and fly safe always.

DJI Stephen Posted at 9-7 20:02
Hello there GeirB. I am sorry for the trouble this has caused and thank you for reaching out. May we please know if you have received any error message or error codes on the DJI Fly application when this happened and just a friendly reminder that DJI do not recommend flying your DJI drone during low light condition as the vision sensors may not work properly. Thank you and fly safe always.

Hey DJI Stephen, sorry for late reply.
Apart from the warning I got about low light and that the vision sensors did not work I did not notice any error messages or codes. I wasn't paying full attention to the screen at all times though, so if the error came and went I might have missed it. At least I can say that I experienced no issues in flying, take off or landing so I was surprised to see how jittery the results were.

Mini 4 dose it during night Hyperlapses - I tried a free flight and even staying on the spot in windless conditions the same effect, but during the day it's OK???

GeirB Posted at 2022-9-6 00:23
Interesting that you have been experiencing the same thing in low light conditions. This makes me think it is indeed using its vision system to maintain course and not GPS + compass.
It's my first real drone too

Hi Geir,

GPS is not used for maintaining drone heading, time of the day does not matter ofcourse.
Heading changes are 'seen' by the compass and the acc meter (rate of heading change) and gyro in the yaw channnel.
In hover, with no RC input, when a position change is there (by wind etc), this change in position (relative to the ground) is 'seen' by GPS.
For the needed correction to get back to the previous position compass/yaw heading data is needed.
Why ; to know wich motors needs more rev and less revs to steer in the correct (opposite) heading.

Vision system helps to keep craft more stable at position, that is why hovering at night is less stable than hovering in daylight (if vision is in range ofcourse)

This must be the reason that a night flown timelapse is not as yaw stable as flown during daylight.

cheers
JJB

alex_markov Posted at 1-31 01:04
Mini 4 dose it during night Hyperlapses - I tried a free flight and even staying on the spot in windless conditions the same effect, but during the day it's OK???

https://youtu.be/EFp3sXv8Q7s

The jitter in movement is substantial I'd say - it's basically telling me that hyperlapse in low-light conditions are not really supported. I've also upgraded to the Mini 4 Pro, but haven't tried it during nighttime.

JJB* Posted at 1-31 01:29
Hi Geir,

GPS is not used for maintaining drone heading, time of the day does not matter ofcourse.

So based on your comments it seems to me that it relies heavily on the vision system to keep its heading and that explains why it is so unstable. The above post from alex_markov clearly seem to indicate that hyperlapse does not produce satisfactory results in low light conditions.

GeirB Posted at 2-2 00:42
So based on your comments it seems to me that it relies heavily on the vision system to keep its heading and that explains why it is so unstable. The above post from alex_markov clearly seem to indicate that hyperlapse does not produce satisfactory results in low light conditions.

Hi,

I wrote my post mainly to make clear that GPS is not used for heading stability.

Why there is een difference in day and night performance for heading stability, it is more complicated i guess and not 100% clear (for me).

Vision helps to maintain hover stability at daylight WHEN is in Vision range ofcourse.

Forward flight and hover heading stability at daylight, out of Vision range, is  perfect.
No heading problems during a daylight Hyperlapse in or out of vision range.

But why at night heading performance is not as good as in daylight?Vision does not work in low light conditions, but during daylight out of range Vision does not work either.

So question remains a valid question, why that difference in performance.

I once taped the bottom vision sensors on a Mini3pro. Hover performance not as good as normal, my drone hovering at low height above the ground.

Nice idea to do some tests with my Mini4pro, hyperlapse in daylight (in and out vision range) and at night with taped/ no tape on the bottom vision sensors.

cheers
JJB