360 deg panorama problems

[agatek]

Hi,
The 360 panoramas coming from the dji stitching software are always displaced as in the image below (please see the horizon line). Initially I thought this was because of strong(er) wind, but having recorded a good few dozens of panoramas under various condition with all of them having the artifacts as bad as presented below it seems something is wrong. I do not recall this sort of problems with mini 2. Perhaps something should be calibrated? I noticed in most of the photos/videos the horizon line is slightly tilted.

View attachment dji_fly_20240715_101554_0101_1721022443348_pano-lq.jpg
Marcin

 

[AeroJ]

Yep, that's definitely weird behaviour. AND the place it goes most wrong (sea / sky horizon) is the area you'd most expect it to have least problems stitching ! Every single one of mine so far has come out with perfect seams (or imperceptibly close to it), but then again I have never found a vista with a perfectly straight horizon like that (haven't made it out to sea with mine yet !) so perhaps it does struggle with that more than I thought ?

I do suspect the wind though in a marine environment - there is usually quite a level of prevailing, directional wind, and then separate, more chaotic and turbulent stuff constantly changing as well as that, so it would be easy to see why a craft that is trying to precisely rotate and angle its camera might struggle to do that consistently. But then again, you say the Mini 2 did fine under the same circumstances.

I presume you have done a gimbal calibration on the ground recently ? No idea if it would make any difference under those windy conditions, but it would be the obvious thing to try first I guess...

Otherwise, next step would be to find a properly windless location and try one there.

 

[MS Coast]

Hi,
The 360 panoramas coming from the dji stitching software are always displaced as in the image below (please see the horizon line). Initially I thought this was because of strong(er) wind, but having recorded a good few dozens of panoramas under various condition with all of them having the artifacts as bad as presented below it seems something is wrong. I do not recall this sort of problems with mini 2. Perhaps something should be calibrated? I noticed in most of the photos/videos the horizon line is slightly tilted.

View attachment 176427
Marcin

I'm not seeing any overall tilt in the horizon. Gimble tilt is adjustable, but there's no indication that it's needed here.

I see similar discontinuities in panoramas I shoot with large expanses of water on the horizon. I'd have thought that the DJI algorithms would do a better job of handing such a simple and high contrast thing as the sky/water interface.

 

[SethB]

It seems to me that waves that move between shots introduce a huge number of variables for the stitch. Yet the waves, which are higher contrast than the horizon line, seem to have fewer errors than the horizon.

I would guess that the broken horizon is the result of the forced alignment of the waves, which would otherwise show more ghosting and misalignments.

 

[agatek]

Yep, that's definitely weird behaviour. AND the place it goes most wrong (sea / sky horizon) is the area you'd most expect it to have least problems stitching ! Every single one of mine so far has come out with perfect seams (or imperceptibly close to it), but then again I have never found a vista with a perfectly straight horizon like that (haven't made it out to sea with mine yet !) so perhaps it does struggle with that more than I thought ?

I do suspect the wind though in a marine environment - there is usually quite a level of prevailing, directional wind, and then separate, more chaotic and turbulent stuff constantly changing as well as that, so it would be easy to see why a craft that is trying to precisely rotate and angle its camera might struggle to do that consistently. But then again, you say the Mini 2 did fine under the same circumstances.

Under similar condition, e.g., same place. Statistically - I do not recall this sort of distortions to happen frequently form mini 2.
If the wind is strong there is typically a warning... but strong for the gimbal may not be the same as for the craft.
Perhaps a good idea would be to take the mini 4 and mini 2 and check how they perform in the same spot, roughly same time....

 

[agatek]

I'm not seeing any overall tilt in the horizon. Gimble tilt is adjustable, but there's no indication that it's needed here.

I see similar discontinuities in panoramas I shoot with large expanses of water on the horizon. I'd have thought that the DJI algorithms would do a better job of handing such a simple and high contrast thing as the sky/water interface.

View attachment 176428

A single image I pasted elsewhere:

There is some optical distortion I guess too (wide lens) but there seems to be some tilt.

Here is another example of the distortions with the horizon somewhat more populated:
View attachment dji_fly_20240623_081334_0037_1719110652553_pano (1).jpg

 

[agatek]

It seems to me that waves that move between shots introduce a huge number of variables for the stitch. Yet the waves, which are higher contrast than the horizon line, seem to have fewer errors than the horizon.

I would guess that the broken horizon is the result of the forced alignment of the waves, which would otherwise show more ghosting and misalignments.

It may be the case (or a similar effect). The 2nd panorama (I just posted) has even more severe distortions but hard to guess whether they originated from the beach or the horizon. It is like two or three tiles got shifted up or down for some reason.

 

[scro]

I've often had problems stitching 360 panoramas with a large sea/sky interface. Both the clouds and the waves (the only real detail in large parts of the frame) are dynamic and are likely to change slightly relative to each other between shots. I've seen the problems both in the DJI autogenerated panoramas and also with putting the original stills into good quality stitching software on a PC.

 

[PanoVolo]

yes, large waves present a problem for stitching as control points shift between the shots.

you can try our software - PanoVolo - and see if results are better

 

[PanoVolo]

also, we have a guide on how to fix the stitching errors manually:

How to Correct Stitching Errors : Panorama Stitching Tool for Drone Photography

HOW TO IDENTIFY AND CORRECT PANORAMA STITCHING ERRORS How to correct stitching errors with PANOVOLO PANOVOLO employs a robust algorithm for drone panorama stitching, utilizing image position and orientation data captured by the drone along with powerful image processing and feature matching...

www.panovolo.com

 

[agatek]

yes, large waves present a problem for stitching as control points shift between the shots.

you can try our software - PanoVolo - and see if results are better

Actually I bought it already, but the results for the automatic stitching are unfortunately not better than for the Dji app.
For the manual correction there is another problem - the resolution of the review images is so low that the stitching appears ok. Only in the rendered panoramas the misalignment is well visible. Can the resolution of the review images be increased? Or, I just do something wrong?

 

[kursat26]

Do panorama errors persist on updated devices?

 

[PanoVolo]

Actually I bought it already, but the results for the automatic stitching are unfortunately not better than for the Dji app.
For the manual correction there is another problem - the resolution of the review images is so low that the stitching appears ok. Only in the rendered panoramas the misalignment is well visible. Can the resolution of the review images be increased? Or, I just do something wrong?

Hi Agatek, thanks for being a customer

the quality between in-drone stitching and PanoVolo stitching is definitely not the same. We can stitch from DNGs and we don't restrict the resolution, unlike in-drone stitching. As for stitching errors, well they happen for sure, many factors can contribute, but moving objects between the frames is one of the major ones.

The resolution of images on review page is low - 1 Mpx. There is no way we can do an on the fly image warping with full res images for editing, it requires way too much processing power. That being said, I'm usually able to correct most stitching problems with a couple of tries, the key is to do incremental adjustments with very small movements and re-render to check the result.

 

[agatek]

Hi Agatek, thanks for being a customer

the quality between in-drone stitching and PanoVolo stitching is definitely not the same. We can stitch from DNGs and we don't restrict the resolution, unlike in-drone stitching. As for stitching errors, well they happen for sure, many factors can contribute, but moving objects between the frames is one of the major ones.

The resolution of images on review page is low - 1 Mpx. There is no way we can do an on the fly image warping with full res images for editing, it requires way too much processing power. That being said, I'm usually able to correct most stitching problems with a couple of tries, the key is to do incremental adjustments with very small movements and re-render to check the result.

Worked with it a bit longer. Agree. It takes some practicing (and switching off some of the screen markings) but seems possible.

BTW, the application keeps crashing during the rendering on my Inspiron 14 5430, 16GB ram, i7-1360P, W11 with all recent updates, PanaVolo 1.6.0 and 1.7.0.
Another feedback, I greatly miss an option to save the project.

 

[agatek]

Do panorama errors persist on updated devices?

I believe I keep them updated but will check next time.

 

[PanoVolo]

Worked with it a bit longer. Agree. It takes some practicing (and switching off some of the screen markings) but seems possible.

BTW, the application keeps crashing during the rendering on my Inspiron 14 5430, 16GB ram, i7-1360P, W11 with all recent updates, PanaVolo 1.6.0 and 1.7.0.
Another feedback, I greatly miss an option to save the project.

I will DM you instructions for getting the crash log in Windows.

As for the project file. PanoVolo saves the .pan file when you manually edit panorama. The file is automatically saved when you edit your panorama in "Review" tab and press "Render". It is also automatically detected and applied next time you stitch. The file contains the manual adjustments for camera positions (when you correct for stitching errors) and for manual adjustment of panorama central point. So there is a project file but it does not require manual save, it is saved and loaded automatically when you edit. In 1.7 when a .pan file is applied you will get a message in the status bar that looks like this:



The file is saved into the source directory, where your initial panorama files are located.