360 spherical panoramas from drone - zenith problem

[C McMillan]

I'm new to this forum and would like to know if anyone has any experience with using PTGui to stitch together multiple shots from on high with a UAV. The camera is working fine, getting great shots, but I always finish with a huge black hole at top of sphere due to my camera being directly below the aircraft and camera only tilting up at a certain angle. I see plenty of tutorials for fixing the floor of a shot (nadir?) presumably due to tripod in view etc.....but almost nothing about preventing or fixing the zenith... the sky directly above. Is anyone aware of any helpful videos to explain each step? I have an iMac, but most PTGui tutorials seem to cover Windows and Mac adequately.

[Erik Krause]

Am 07.02.2017 um 12:23 schrieb C McMillan:
> I always finish with a huge black hole at top of sphere due to my
> camera being directly below the aircraft and camera only tilting up
> at a certain angle.

The easiest is to shoot the sky from the ground. Turn your drone round
pointing the camera to the sky and take some shots best with the horizon
on the edge. Then in PTGui after stitching the regular panorama add
those shots and position them roughly. Two or three control points on
subjects on the horizon might help. Don't create control points
automatically or use Align Images! Optimize again (pressing F5). This
should do it...

--
Erik Krause

[C McMillan]

Thanks Eric....

I've been checking lots of sites to fix the problem and appreciate your suggestion,

However I've managed to get the image to this stage now (see attachment)

As you can see, it looks reasonable apart from the way the edges have been joined after I did a bit of cloning.

Any simple way to correct this please?

[Erik Krause]

Am 09.02.2017 um 22:41 schrieb C McMillan:
> However I've managed to get the image to this stage now (see attachment)

please do not add attachments or images to your posts; instead upload
your files at a file sharing site (for example http://sendspace.com// )
and include a link in your message.

> As you can see, it looks reasonable apart from the way the edges have been
> joined after I did a bit of cloning.
> Any simple way to correct this please?

You'd need to do the cloning on an extracted rectilinear image. If you
do it in the equirectangular image you always get these artifacts. You
can use my templates which are originally for floor extraction and
insertion from http://www.erik-krause.de/ttt/#Bodenbild_extrahieren
To use it for sky you need to change the pitch value on Image Parameters
tab from 90 to -90 or vice versa for the respective image after you
applied either template. More instructions in the download.

--
Erik Krause
http://www.erik-krause.de

[Vincent Noben]

Hello Erik,

Many thanks for your wonderfull work.

I have some DJI Mavic Air drone footage which has a large zenith hole.
I used your "Extract floor" template to extract the zenith by doing a 180 pitch shift and adjust the sliders to a 120° x 120° rectiliniar projection.
I patched the hole in photoshop with a content aware fill and that looks perfect.

But I cannot seem to find a way to stitch both images back together using your template.
As it puts my new sky on the Nadir and shifting in any direct shifts both layers, even if I select just one.
Any idea's on how to do that?


Op donderdag 9 februari 2017 22:57:29 UTC+1 schreef Erik Krause:

[Vincent Noben]

Hi again Erik,

You can ignore my question, I figured it out.
For your interest, see attachment image

I played with those settings until it matched perfectly.
Saved it as a template for future use.
Thanks anyways !

Op woensdag 27 februari 2019 00:17:50 UTC+1 schreef Vincent Noben:

[Erik Krause]

Am 27.02.2019 um 00:17 schrieb Vincent Noben:

> Any idea's on how to do that?

The easiest is to change the pitch settings from 90 to -90 and vice
versa in both templates. No need to change the panorama beforehand.

Originally I didn't want to update the templates for PTGui 11, because
there is the possibility to create and re-assemble cube faces now. But I
didn't think of large zenith holes which require more than 90°. I guess
I find some time in the coming days to do the update and add a zenith
template as well...

[uricogan]

To limit the upward look angle (nothing to see there...) in KRPANO,  all I need to do is edit the .xml file thus:  

  

<view limitview="lookat" vlookatmin ="90"  vlookatmax ="11"/>

[Vincent Noben]

Hi Erik,

Thanks, that would be wonderful for other users.
I've made my own templates for now and have been patching panorama's like never before ;)
Thanks

I was thinking about making a little video tutorial on how to patch those large zenith holes for drone footage.
Will update you if I find the time. Might be handy to add as a note to your templates.

Vincent

Op woensdag 27 februari 2019 09:48:37 UTC+1 schreef Erik Krause:

[Herwig Niggemann]

A very convenient method for me to fill the sky is using a 360 photo editor: Affinity Photo does just that.

A take the ready ptgui equirectangular lpad it into Affinity Photo. The change the view to Menue Layers - > Live Projection and choose Equirectangular projection. 

A select the black part of the zenith with the magic wand, then fill it with a colour of the sky by taking a average point with the selection tool. This gives you an pretty good fill similar to the rest of the sky. Then I take Clone tool and copy some typical areas from the sky into the top area so it loosk similar. After 2-3 minutes, its done. Change the aspect back to "remove projection" and export it to the size you want. Ready. 

This works without taking other photos and try to put it in. 

Actually DJI creates a similiar type of fake sky in the automatic version of Panorama on the Magic 2 Pro. 

Here are two examples:

https://roundme.com/tour/343433/view/1149569/

https://roundme.com/tour/330795/view/1095360/

the last tour has three versions: 

- Mavic Pro2 stitched in camera and sky filled artificial

- PTGUI stitched without fill

- PTGUI stitched with Skyfill via Affinity Photo. 

Herwig