Mini moves during hover -> very poor manually created HDR photo's

[Droning on and on...]

My mavic mini is a great piece of tech,
However I was hoping to be able to create HDR pictures and even HDR panorama's using the mavic mini by manually bracketing shots, so taking the same picture multiple times (underexposed, normally exposed and overexposed).
Unfortunately, the HDR pictures I generate this way are horrible.
I noticed that while the mini hovers it does move a little.
Here are two 200*200 pixel cut-outs from the bottom-right corner of two 12 megapixel photos.
As you can see the mini clearly moved in between both shots (even if it looks worse than it is, because this is a tiny portion of a much larger photo).



It wasn't particularly windy and i've made quite a few attempts at different occasions without luck.
Now you might say: it's a thing that flies, how can you expect it to stand perfectly still?
I would be able to accept that argument, but then I don't understand how others are able to make great HDR pictures using the mavic mini.
I've done the compass calibration and IMU calibration just before taking the above shots.

I'd appreciate your advice (is this motion normal? If not, what can I do about it? If it is normal: how to others get such great HDR shots and even HDR panorama's?
Many thanks!

 

[Paul51]

There are 2 sources of video from the Mavic Mini. The controlling device, and the Micro SD card installed in the Mini itself.

The device video is "poor quality" The Micro SD card is high quality.

Hope this helps.

 

[Deleted member 103366]

I find that the mini moves very little when well within the working range of the vision sensors on the bottom, i.e. low down, but it is harder to assess movement as it climbs above head height. Once it is above vision sensor range I would expect some wander as GPS position holding is not pin point.

 

[scro]

You can layer multiple exposures in photoshop and then align them prior to merging into an HDR.

@PhiliusFoggg beat me to it.... if you stay under 10m altitude the VPS will help keep the mini hovering in 1 spot. It's not perfect, but it's better than just GPS.

If you need more altitude try ensuring nothing in the picture is too close to the drone and that will help keep everything in the frame the same.

 

[Ramjam61]

Lots of practice. I have an £800 canon eos 800d. A proffesional can spark that into life, I can only shoot on auto at the mo. Keep practising.

 

[Droning on and on...]

There are 2 sources of video from the Mavic Mini. The controlling device, and the Micro SD card installed in the Mini itself.


The device video is "poor quality" The Micro SD card is high quality.


Hope this helps.

Thanks, but I' m taking the 12MP photos from the SD-card.

I find that the mini moves very little when well within the working range of the vision sensors on the bottom, i.e. low down, but it is harder to assess movement as it climbs above head height. Once it is above vision sensor range I would expect some wander as GPS position holding is not pin point.

Thanks for the insight! I will try taking pictures tomorrow while staying below 10m as advised by @scro. I assume there's no indicator that shows whether the vision sensors are being used or not?

If you need more altitude try ensuring nothing in the picture is too close to the drone and that will help keep everything in the frame the same.

I assume the reasoning here is that if the drone moves a little, this will be more noticeable on objects that are close than objects that are far away?

Lots of practice. I have an £800 canon eos 800d. A proffesional can spark that into life, I can only shoot on auto at the mo. Keep practising.

I do have over a decade of experience making HDR pictures, and close to 20 in making panorama's. but then I was using a camera on a tripod, not a drone flying in the air...

 

[PanX]

Some HDR dedicated programmes do automatic picture alligment.

 

[Droning on and on...]

I've tried to make the HDR photo's with lightroom (not a very recent version) Photoshop, and for the HDR panoramas I also tried ptgui. Which programme do you recommend?

 

[PanX]

I've tried to make the HDR photo's with lightroom (not a very recent version) Photoshop, and for the HDR panoramas I also tried ptgui. Which programme do you recommend?

Picturenaut Overview this (its free) has automatic photo alligment.

 

[Bussty]

I've tried to make the HDR photo's with lightroom (not a very recent version) Photoshop, and for the HDR panoramas I also tried ptgui. Which programme do you recommend?

If you invest in the time to learn it and go through all the online help PTGUI will allow you to stitch and align almost anything even images were parallax has become an issue. You can mask out areas, manually align tricky panos, export to layers so you can manually blend. Good luck!

 

[SkyeHigh]

I find that the mini moves very little when well within the working range of the vision sensors on the bottom, i.e. low down, but it is harder to assess movement as it climbs above head height. Once it is above vision sensor range I would expect some wander as GPS position holding is not pin point.

It’s not just using GPS to maintain position. The IMU also uses a 3-axis gyro and 3-axis accelerometer and uses this to help maintain it’s position when hovering - and to keep the gimbal steady (as well as during flight).

Make sure that the AC isn’t in ATTI mode, with this you can expect some drift as it is not using GPS - usually due to poor satellite coverage.

Also check the joysticks are fully centred. If not correctly calibrated they can lead to some movement - though rare.

There is no reason that a stable image cannot be achieved if the AC is working correctly and it is within it’s wind handling capabilities.

 

[Droning on and on...]

Thanks for the tips so far!
The AC isn't in ATTI mode and I checked and to my eyes the joysticks are centred.
I tested hovering while staying below 10 meters, but there was still a lot of movement in between pictures.
I made a little video showing:
- 14 seconds of hovering at low altitude, so in principle with the vision sensor (4 times sped up)
- 6 seconds of hovering at high altitude, so in principle without the vision sensor (4 times sped up)
- after that there is the same footage, but at normal speed (while the range of motion in the sped up footage is the same, it does make the amount of motion seem much worse than it is)
What do you think? Is this level of movement to be expected? Or is it more than usual?

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[scro]

Seems to be similar to what I get, and in line with the published specs for hover accuracy. You're quite close to the things in the camera view so there'll be noticable movement on the video. If you were 10m up and looking out over a field the same amount of drone movement would be barely perceptible in the video.

 

[Meta4]

I noticed that while the mini hovers it does move a little.
I'd appreciate your advice (is this motion normal? If not, what can I do about it? If it is normal: how to others get such great HDR shots and even HDR panorama's?

Is it normal?
Here's what the specs say:
Hovering Accuracy Range
Vertical: ±0.5 m (with GPS Positioning)
Horizontal: ±0.3 m ±1.5 m (with GPS Positioning)

If the subject if close to the camera, you will see differences between shots.
If the subject is further away, the differences will be less.

 

[Droning on and on...]

OK Thanks! and is this motion that I had yesterday when trying to make a HDR picture also to be expected?

 

[scro]

That amount of motion seems excessive, especially the yaw. Were the frames taken in fairly quick succession? Was the wind quite variable?

However, aligning the 3 exposures prior to merge should still give a good result as the parallax should be minimal.

 

[Dave Maine]

Most alignment programs allow the user to specify how much mis alignment is allowed before giving up.

 

[Made2Phly]

Aurora is a great HDR program, but expensive.

 

[Deleted member 103366]

With regards to the video in post #12 that seems quite good to me.
However I would add the following to my original post. I have noticed that when the mini is flying in the house it seems able to detect movement in what the vision sensors see. I happened to notice that if there was the likes a flapping sheet of paper (flapping due to the drone's downdraft) in its view it moved more than if it saw only short pile carpet or stationary objects. This additional movement was still small and reasonably rapid and distinctly different from the movement seen when only carpet etc. was in view. It disappeared as soon as I removed the paper from view and reappeared if I replaced the paper. I'd guess similar movement might occur over vegetation that could be blown about by the down draft.
With regards to post #15 I am wondering what would happen if you cropped all the images so that they contained the same material, would they stack or layer more easily?

 

[SkyeHigh]

The weather looks good tomorrow so I’ll give it a go with my M2P and see what happens.