Stiching with blue sky

375 views
Skip to first unread message

aperture

unread,
Aug 3, 2011, 6:34:50 AM8/3/11
to PTGui Support
I am having problems stiching large areas of blue sky without any
features such as clouds etc. There is a lack of control points.

How do you overcome this and how do you add control points to an
otherwise featureless zone ?

Regards

Ken Warner

unread,
Aug 3, 2011, 6:42:36 AM8/3/11
to pt...@googlegroups.com
You don't have to have control points in an all blue sky image.

Here's a few ways to do it:

1) Try the new PTGui beta. It allows one to roughly position
images to approximately where they should be using Align to Grid feature.
Works pretty good.

2) If you are using a pano head, use Fill Yaw at the bottom
of the Image Parameters tab. Set the pitch to what you shot
at and Roll to 0.

3) Use the Panorama Editor to roughly position the sky images.
You can use the flare from the Sun to figure out where the images
should go.

Once they are in about the right place you can optimize and those
images will not move but they will be blended properly.

John Houghton

unread,
Aug 3, 2011, 7:01:22 AM8/3/11
to PTGui Support
In addition to the ways suggested by Ken, if you shot an old project
in exactly the same way, you can use the project file as a template to
initialize the positions of all the images and also the lens
parameters (File->Apply template). Generate control points and
optimize: the orphan images should stay well aligned without any
control points. They will also remsain aligned when the panorama is
levelled with t1/t2 control points.

John

aperture

unread,
Aug 3, 2011, 8:15:27 PM8/3/11
to PTGui Support
Ken

have downloaded the beta 1. i am able to shift around frames manually
but it still wont let me create a panorama ( ie the create panorama
button will not highlight for selection ).
how do you create the panorama once you have manually shifted the
frames around to resemble their approximate location ?

Ken Warner

unread,
Aug 3, 2011, 9:15:20 PM8/3/11
to pt...@googlegroups.com
I'm not sure what is going wrong but here is what I do:

1) If it's a pano with details that will support CP's in
all images -- just hit the Align button on the first tab.

2) If it's a "big blue bowl" type image with blank skies or
clouds that aren't good for CP's -- I'd use the Align to Grid
first to get the images in approximately the right place -- then
hit the Align button on the first page.

3) After 1) or 2) you still have to optimize to get the images
positioned ready for stitching.

Maybe your problem is that you haven't generated any CP's That still
needs to be done after the Align to Grid.

John Houghton

unread,
Aug 4, 2011, 2:30:26 AM8/4/11
to PTGui Support
On Aug 4, 1:15 am, aperture <scott.burr...@aperture.com.au> wrote:

> have downloaded the beta 1. i am able to shift around frames manually
> but it still wont let me create a panorama ( ie the create panorama
> button will not highlight for selection ).

Probably you are referring to the Create Panorama button on the
Project Assistant tab. That does not become active until you have
completed the previous steps in processing the camera images. If you
want to bypass these, click on the Advanced button on the right. You
will then have access to the Create Panorama tab, where you can
customize the output parameters and create the output image.

John

Istvan Takacs

unread,
Aug 4, 2011, 3:07:23 PM8/4/11
to pt...@googlegroups.com
Hello,

"should be using Align to Grid feature"

sorry but where and how? I cannot find!

Thank you!

Istvan

> --
> You received this message because you are subscribed to the Google Groups
> "PTGui" group.
> To post to this group, send email to pt...@googlegroups.com
> To unsubscribe from this group, send email to
> ptgui+un...@googlegroups.com
> Please do not add attachments to your posts; instead you may upload files at
> http://groups.google.com/group/ptgui/files
> For more options, visit this group at http://groups.google.com/group/ptgui

Istvan Takacs

unread,
Aug 4, 2011, 3:12:35 PM8/4/11
to pt...@googlegroups.com
ok, forget it! I have find! :)

Ken Warner

unread,
Aug 4, 2011, 3:14:17 PM8/4/11
to pt...@googlegroups.com
Project -> Align to Grid

Kalain

unread,
Aug 6, 2011, 4:35:23 AM8/6/11
to PTGui Support
Hi,

Here is workflow under 9.1 beta 1 from which I didn't succeed to
stitch 33 images. (3 columns of 11 images)

1/Load images :
- select 33 images.

2/Project -> Align to grid :
- select right settings.
- Apply button
- All images are perfectly aligned in preview window. (View result
in Panorama editor)

3/ Align To Images :
- 13 images have no CP.
- 3 images are stacked onto one : Nro 0/6/17 onto nro 17.
- Preview is bad compared at Align to Grid preview.

4/ Create panorama buton is not enabled.

mmh!
I suspect a bug here or I do not use correctly Align to Grid feature.

Any advise or help on how to use this feature ?

I should probably better wait some doc on this feature.

Ken Warner

unread,
Aug 6, 2011, 4:59:59 AM8/6/11
to pt...@googlegroups.com
Is it 3 rows (horizontal) or 3 columns (vertical)?

What is your Panorama Settings? Is it Equirectangular with
Field of view 360 horizontal and 180 vertical?

I'm at the limit of my ability to help. Sorry.

Kalain

unread,
Aug 6, 2011, 5:12:45 AM8/6/11
to PTGui Support
It has been taken by home made motorized pano head.
Full pano is 81 columns of 11 images. (@450mm at FX equiv)
As I just want to test new beta feature, I just take 3 columns. (much
more faster to proceed on my small computer)

Ken Warner

unread,
Aug 6, 2011, 5:24:59 AM8/6/11
to pt...@googlegroups.com
I can't help with that. Somebody else who knows more
might be able to help.

Kalain wrote:
> It has been taken by home made motorized pano head.
> Full pano is 81 columns of 11 images. (@450mm at FX equiv)
> As I just want to test new beta feature, I just take 3 columns. (much
> more faster to proceed on my small computer)
>

PTGui Support

unread,
Aug 6, 2011, 11:06:37 AM8/6/11
to pt...@googlegroups.com
Hi Alain,

Did you shoot the panorama around the horizon? I mean is there as much above as below the horizon? Currently it is important to set the proper pitch angle so that after you do Align To Grid the horizon is on the center line of the panorama editor.

Joost

John Houghton

unread,
Aug 6, 2011, 11:07:42 AM8/6/11
to PTGui Support
On Aug 6, 9:35 am, Kalain <kalain.pie...@free.fr> wrote:
> I suspect a bug here or I do not use correctly Align to Grid feature.
>
> Any advise or help on how to use this feature ?

You say that the images are perfectly aligned in the Panorama Editor
window, so clearly the Align to Grid feature has worked perfectly.

What you need help with is how to use PTGui generally and the
Optimizer in particular. You are obviously using PTGui in Simple mode
via the Project Assistant and for large complex projects like the one
you are attempting, I think you will need to venture into Advanced
mode and take more control over what is happening. The Project
Settings tab determines what is done when you use the Align Images
feature. If the "Roughly arrange images" option is checked, the good
work done by Align to Grid might well be undone.

John

PTGui Support

unread,
Aug 6, 2011, 11:14:37 AM8/6/11
to pt...@googlegroups.com
It should not be necessary to switch to Advanced mode actually (but feel free to explore it of course).

Even with 'roughly arrange images' enabled the optimizer should be able to keep orphaned images together with the panorama.

Please try my previous suggestion (see if the panorama is centered around the horizon); if that does not help I would like to have a copy of the project files - after all it's a beta feature.

Joost

Kalain

unread,
Aug 6, 2011, 12:16:39 PM8/6/11
to PTGui Support
Hi,

I think I missed how to use this new feature or there is a bug around
here.

My problem is, I can't get a valid "Create panorama" button because
some pictures has some blue sky and do not have any common CP.

Here is workflow :

1/Load images :
- select 33 images.

2/Project -> Align to grid :
- select right settings. (3 columns of 1 images, 40% overlap.)
- Apply button
- In preview window, All images are perfectly aligned onto selected
grid. (3 columns of 11 images)

3/ "Align To Images" button is pressed :
Result :
- 13 images have no CP.
- 3 images are stacked onto one : Nro 0/6/17 onto nro 17.
- Preview is bad compared at Align to Grid preview. (Images are not
anymore perfectly aligned onto predefined grid. (3*11 images)

4/ Create panorama buton is not enabled.
This is the trick.

Yes, I'd like to share these 33 images for those who want to try.
I will try to upload them in a server.

John Houghton

unread,
Aug 6, 2011, 1:56:11 PM8/6/11
to PTGui Support
On Aug 6, 4:14 pm, PTGui Support <supp...@ptgui.com> wrote:

> Even with 'roughly arrange images' enabled the optimizer should be able to keep orphaned images together with the panorama.

Joost, Does 'roughly arrange images' take any account of the existing
layout or does it start from scratch or make use of the data that now
happens to be available on the Align to Grid panel?

John

Kalain

unread,
Aug 7, 2011, 2:54:19 AM8/7/11
to PTGui Support
Let's start an example.

Create 4 Jpeg files with Paint.
Each files is colored as red, yellow, blue, green.
There is no CP between each images. (Like blue sky in certains pano
images.)

1/ Create a project in PTGui.
2/ Load these 4 images.
3/ Align to Grid. (2 * 2)
Now, these 4 images are perfectly aligned in a 2*2 grid.

What's next in order to have a stiched pano ?

Thanks

John Houghton

unread,
Aug 7, 2011, 7:53:59 AM8/7/11
to PTGui Support
Assuming you are satisfied with the general appearance of the panorama
in the Panorama Editor window:

1. Select Advanced mode via button on the Project Assistant.
2. Select the Create Panorama tab.
3. Click Set Optimum Size->Maximum Size
4. Choose output file format and select Blended Panorama Only from
Layers options.
5. Click Create Panorama.

John

Kalain

unread,
Aug 8, 2011, 2:57:53 AM8/8/11
to PTGui Support

> Assuming you are satisfied with the general appearance of the panorama
> in the Panorama Editor window:

Yes, general appearance in panorama editor window seems correct.


> 1. Select Advanced mode via button on the Project Assistant.
> 2. Select the Create Panorama tab.
> 3. Click Set Optimum Size->Maximum Size
> 4. Choose output file format and select Blended Panorama Only from
> Layers options.
> 5. Click Create Panorama.

Ouch!
Even if general appearance seems ok in Panorama Editor window, this is
not enough to stich them correctly without any CP!
Now, if I press "Align image" to generate CP, my 33 images (for this
example) are not any more positioned with the setting grid. (3 col of
11 images)
Some images are piled onto one image.
By pressing "Align image" button, I loose the benefit of "Align to
grid" feature!

So, I don't know (didn't find) how to proceed and achieve a pano with
blue sky.

Should probably wait beta 2.

PTGui Support

unread,
Aug 8, 2011, 5:45:00 AM8/8/11
to pt...@googlegroups.com
Hi John,

'roughly arrange images' does a fresh start and arranges all images that
have control points from scratch. Then (and this is new in this beta) it
will attempt to arrange the orphaned images in such a way that the
geometry of the panorama is preserved. This only affects the orphaned
images (or orphaned clusters), the alignment of images within a cluster
is not affected.

Joost

PTGui Support

unread,
Aug 8, 2011, 5:47:00 AM8/8/11
to pt...@googlegroups.com
Hi Kalain,

Without seeing the project I have not idea what the problem might be, so
can you make your project available?

Joost

PTGui Support

unread,
Aug 8, 2011, 5:57:33 AM8/8/11
to pt...@googlegroups.com
The next step would be to press Align Images. In this case it would not
do anything since it can't find control points.

Then you would go to Create Panorama to stitch it.

If you can't figure it out it would be helpful if you post the project,
otherwise we would keep theorizing over the many things that might have
gone wrong somewhere in the process (this includes possible bugs in the
beta btw)..

Joost

John Houghton

unread,
Aug 8, 2011, 8:12:24 AM8/8/11
to PTGui Support
On Aug 8, 7:57 am, Kalain <kalain.pie...@free.fr> wrote:
Panorama.
>
> Ouch!
> Even if general appearance seems ok in Panorama Editor window, this is
> not enough to stich them correctly without any CP!

It is quite possible to have images that don't even overlap but are
accurately positioned to butt together and these (necessarily without
control points) can be stitched perfectly - but not automatically.

If you want to use Align to Grid, assign control points, and then
optimize in such a way that any orphan images do not change their
position by as much as a pixel, then you can easily do it.

John

Kalain

unread,
Aug 9, 2011, 1:47:29 AM8/9/11
to PTGui Support
On 8 août, 11:57, PTGui Support <supp...@ptgui.com> wrote:
> If you can't figure it out it would be helpful if you post the project,
> otherwise we would keep theorizing over the many things that might have
> gone wrong somewhere in the process (this includes possible bugs in the
> beta btw)..

Here is a link to download 33 images (3 columns of 11 pict each.)
http://www.files.to/get/18817/0brrvpa9wd

Nota : Full pano has 79 col.

Eric O'Brien

unread,
Aug 9, 2011, 2:22:49 AM8/9/11
to pt...@googlegroups.com
See my comment, part way down...

On Aug 7, 2011, at 11:57 PM, Kalain wrote:

>
>> Assuming you are satisfied with the general appearance of the panorama
>> in the Panorama Editor window:
>
> Yes, general appearance in panorama editor window seems correct.
>
>
>> 1. Select Advanced mode via button on the Project Assistant.
>> 2. Select the Create Panorama tab.
>> 3. Click Set Optimum Size->Maximum Size
>> 4. Choose output file format and select Blended Panorama Only from
>> Layers options.
>> 5. Click Create Panorama.
>
> Ouch!
> Even if general appearance seems ok in Panorama Editor window, this is
> not enough to stich them correctly without any CP!
> Now, if I press "Align image" to generate CP, my 33 images (for this
> example) are not any more positioned with the setting grid. (3 col of
> 11 images)
> Some images are piled onto one image.

You might try working with a completely different panorama and a completely different set of images, and see how that goes.

When images that *you* know to be different are 'piled on top of each other,' this often indicates that PTGui incorrectly thinks that it has found matching points between those images. If you inspect the Control Points tab and check the "piled up" images, I bet you might find some control points paired between images where you can see that actually they should not be.

This can happen when trying to stitch scenes that have repetitive features. The interior of a cathedral or museum... in a forest... in a sports stadium perhaps.

eo

PTGui Support

unread,
Aug 9, 2011, 3:43:03 AM8/9/11
to pt...@googlegroups.com
Hi Kalain,

I'm getting a reasonably good panorama with these settings in Apply To Grid:

11 rows of 3 images

Horizontal axis:
Center horizontally: yes
Spacing: spaced by 1.5 degrees

Vertical axis:
Topmost pitch angle: 6 degrees
Spacing: spaced by 2.7 degrees

Remember: for good results you should have the angles as accurately as
possible, and the horizon should be in the center of the panorama.

Joost


On 9-8-2011 7:47, Kalain wrote:

Kalain

unread,
Aug 9, 2011, 4:39:55 AM8/9/11
to PTGui Support
Hi,

I tried with these settings below.

Here is some results :
With no CP :

With CP : (but all pict do not have some CP and are not stiched.)

Can you post the full workflow (procedure) you did (as I also posted
previously) ?

Another comment about Grid parameters.
I understand that user have to give some rough parameters at PTgui
like nb row / nb pictper row, rough overlap, ...
Some parameters can't be changed by PtGui (nb row / nb pic per row)
but some other should be adjusted by the software. (overlap.)
When you shoot such pano, you can't remenber exactly what was these
technical settings.

Thanks

Kalain

unread,
Aug 9, 2011, 4:51:45 AM8/9/11
to PTGui Support

Here is some results :
With no CP :
http://www.files.to/get/18833/gh5vg1sc9a

With CP : (but all pict do not have some CP and are not stiched.)
http://www.files.to/get/18834/xjry97nxl1

PTGui Support

unread,
Aug 9, 2011, 4:52:39 AM8/9/11
to pt...@googlegroups.com
Hi Kalain,

I don't see the screenshots in your mail.

Actually I do notice a bug in the beta now, image 0 doesn't get
positioned correctly. Is worked around by pressing 'Align' again in the
Align to Grid window and then reoptimizing.

But let's suspend this discussion until the next beta is released.

Joost

On 9-8-2011 10:39, Kalain wrote:
> Hi,
>
> I tried with these settings below.
>
> Here is some results :
> With no CP :
>
> With CP : (but all pict do not have some CP and are not stiched.)
>
> Can you post the full workflow (procedure) you did (as I also posted
> previously) ?
>
> Another comment about Grid parameters.
> I understand that user have to give some rough parameters at PTgui
> like nb row / nb pictper row, rough overlap, ...
> Some parameters can't be changed by PtGui (nb row / nb pic per row)
> but some other should be adjusted by the software. (overlap.)
> When you shoot such pano, you can't remenber exactly what was these
> technical settings.
>
> Thanks
>
>

Kalain

unread,
Aug 9, 2011, 5:18:23 AM8/9/11
to PTGui Support
Ok, I got it.

Workflow is
1/ Load images (Select pano pictures)
2/ Press "Align Images" button. (to generate CP)
3/ Align to grid. (To Align on a grid pictures with no CP (blue sky,
off focus images, ...))
4/ Create Panorama Tab : Create Panorama button.

Even in this configuration, It seems that pano is stiched without
taking account of CP!

NB : Align to Grid has to be done always at the end. (Always after an
"Align Images" action)

Bug confirmed : Sometimes Image 0 is away in preview window.

Ok, let's see what will be beta 2.

Kalain

unread,
Sep 2, 2011, 3:10:28 PM9/2/11
to PTGui Support
Hi,

On 9 août, 10:52, PTGui Support <supp...@ptgui.com> wrote:
> Hi Kalain,
>
> I don't see the screenshots in your mail.
>
> Actually I do notice a bug in the beta now, image 0 doesn't get
> positioned correctly. Is worked around by pressing 'Align' again in the
> Align to Grid window and then reoptimizing.
>
> But let's suspend this discussion until the next beta is released.

With 9.1 beta 2 seems to work correctly.
I could stich my 33 images given as an example.

Good job for this beta2.

Kalain

unread,
Sep 9, 2011, 2:03:46 PM9/9/11
to PTGui Support
Hi,

On 9 août, 10:52, PTGui Support <supp...@ptgui.com> wrote:
> Hi Kalain,
>
> ....
>
> Actually I do notice a bug in the beta now, image 0 doesn't get
> positioned correctly. Is worked around by pressing 'Align' again in the
> Align to Grid window and then reoptimizing.

After
- Loading 891 images
- Align to grid. (81 columns of 11 images)
- Generate Control Point. (Ctrl+Alt+G)

Everything is correct in Panorama editor.

After "Optimize" (F5), image 0 is stacked at upper left corner of
panorama. (far from image 1, and image 11)

So, bug around image 0 is still there (9.1 beta2)

Alain

Takudzwa Mujuru

unread,
Apr 11, 2020, 3:43:13 PM4/11/20
to PTGui Support
Hello ,

I am having this same problem. I am trying to stitch frames from google earth studio.
I have gone through all replies for this inquiry, I haven't been successful in resolving my issue.



On Wednesday, August 3, 2011 at 6:34:50 AM UTC-4, aperture wrote:
I am having problems stiching large areas of blue sky without any
features such as clouds etc. There is a lack of control points.

How do you overcome this and how do you add control points to an
otherwise featureless zone ?

Regards

PTGui Support

unread,
Apr 11, 2020, 3:57:17 PM4/11/20
to pt...@googlegroups.com
Hi,

Please see 6.28:
https://www.ptgui.com/support.html#6_28

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com
> --
> You received this message because you are subscribed to the Google
> Groups "PTGui Support" group.
> To unsubscribe from this group and stop receiving emails from it, send
> an email to ptgui+un...@googlegroups.com
> <mailto:ptgui+un...@googlegroups.com>.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/ptgui/d24470fa-1083-441b-b9b9-44bf24cd4bc4%40googlegroups.com
> <https://groups.google.com/d/msgid/ptgui/d24470fa-1083-441b-b9b9-44bf24cd4bc4%40googlegroups.com?utm_medium=email&utm_source=footer>.
Reply all
Reply to author
Forward
0 new messages