4x 12 HDR Panorama for real estate (Multirow)

[Manfred Gloiber]

Hello,

I was almost ready to buy PTgui and found Hugin and it looks very mature. Actually too complicated so far ;-)

My situation:

- 48 images (HDR merged already but no settings applied except lens correction and removed chromatic abberation)

- All images were shot with a panorama head and fixed nodal point

- 18mm-28mm Tamron Full Frame Lens, 18mm used but with APS-C crop factor (accidentally)

- 4 rows, 12 columns, 30°

- 1 ceiling picture but I think it's not needed because there are enough images

- Nadir show was bad so it can be skipped or ideally replaced with a logo

My goal:

360° x 180° HDR panorama for a virtual tour

Somehow I can't get the control points detection working good enough. In PTgui there is a "Align to Grid" dialog and control points are detected on overlapping images -> is that possible with Hugin, too?

I mean I know which image is on which position but Hugin doesn't and it finds a lot wrong control points, too.

Generally the workflow is totally confusing and not clear to me to be honest...

I hope I just miss some basic step or tutorial :-)

[Sean Greenslade]

On Tue, Sep 15, 2020 at 09:03:40AM -0700, Manfred Gloiber wrote:
> Hello,
>
> I was almost ready to buy PTgui and found Hugin and it looks very mature.
> Actually too complicated so far ;-)
>
> My situation:
> - 48 images (HDR merged already but no settings applied except lens
> correction and removed chromatic abberation)

One suggestion here: you may not want to apply lens correction. Hugin
will calculate lens correction parameters as part of its optimizations,
so you'll get a better final image with fewer processing steps in the
middle. You may still want to apply the chromatic aberration correction,
since I don't believe the hugin photometric correction handles that.

Hugin can also do HDR stack fusing. If you have the time, I'd suggest
giving it a try and seeing how you like the results.

> - All images were shot with a panorama head and fixed nodal point
> - 18mm-28mm Tamron Full Frame Lens, 18mm used but with APS-C crop factor
> (accidentally)
> - 4 rows, 12 columns, 30°
> - 1 ceiling picture but I think it's not needed because there are enough
> images
> - Nadir show was bad so it can be skipped or ideally replaced with a logo

This can be done in Hugin, though it's probably best to wait until your
pano is aligned and stitches correctly.

> My goal:
> 360° x 180° HDR panorama for a virtual tour
>
> Somehow I can't get the control points detection working good enough. In
> PTgui there is a "Align to Grid" dialog and control points are detected on
> overlapping images -> is that possible with Hugin, too?

If you get the images roughly alinged (either with a template file or
just manually with the fast preview window), you can use the "Hugin's
CPFind (prealigned)" option. This restricts the cpfind process to only
pairs of images that are overlapped. If your rough alignment is good
enough, you could also use the "control point table" to select all
control points above a reasonably large error value and delete them.

> I mean I know which image is on which position but Hugin doesn't and it
> finds a lot wrong control points, too.

The control point finder is definitely not perfect. In some really bad
cases (like images with a lot of identical, repeating patterns), you may
need to just manually insert control points.

> Generally the workflow is totally confusing and not clear to me to be
> honest...
>
> I hope I just miss some basic step or tutorial :-)

Hugin is very powerful and has a lot of advanced features to give very
fine-grained control over the panorama creation process. Broadly
speaking, my workflow on a project like this might be:

1. Import all the images
2. Open Fast Preview and do a rough alignment by hand
3. Apply any necessary masks (e.g. tripod legs)
4. Perform a CPFind (prealigned)
5. Run the "remove control points in masks" macro
6. Check the quality of the control points in the Fast Preview
7. Cull any obviously bad control points
8. Run a geometric optimizer pass on the "positons and view" setting
9. Check the results, tweak problematic control points
10. Run a geometric optimizer pass on the "everything without
translation" setting
11. Final check on alignment, tweak control points and re-run optimizer
12. Run photometric optimizer on "Low dynamic range" setting (use
variable white balance mode if your camera had AWB set)
13. Choose output format, crop, size, etc. and stitch the pano
14. Go back and tweak things if you find issues with the resulting pano

In general, don't be afraid to just play around with Hugin. Of course,
feel free to come back and ask for more help if you get stuck.

--Sean

[Paul Womack]

One suggestion here: you may not want to apply lens correction. Hugin
will calculate lens correction parameters as part of its optimizations,
so you'll get a better final image with fewer processing steps in the
middle. You may still want to apply the chromatic aberration correction,
since I don't believe the hugin photometric correction handles that.

It may be able to to. Is this 2006 article the latest information ?

http://hugin.sourceforge.net/tutorials/tca/en.shtml

   BugBear

[Bruno Postle]

On 16 September 2020 08:57:36 BST, Paul Womack wrote:
>>
>It may be able to to. Is this 2006 article the latest information ?
>
>http://hugin.sourceforge.net/tutorials/tca/en.shtml

Some command-line tools were written to calculate and correct tca (transverse chromatic aberration), and they still ship with Hugin, but this was never implemented in the stitcher or the GUI.

It would complicate the GUI, and stitching would take three times as long. I'm not sure if there is demand now that some cameras do this correction internally and it is available in all raw converters.

--
Bruno

[Paul Womack]

On Wed, 16 Sep 2020 at 09:13, Bruno Postle <br...@postle.net> wrote:

It [TCA] would complicate the GUI, and stitching would take three times as long. I'm not sure if there is demand now that some cameras do this correction internally and it is available in all raw converters.

I think it would only increase the generation of the mapped images by three times. Stitching (enblending...), which is normally the slower process (at least for me) would be unaffected.

   BugBear

[Bruno Postle]

On 16 September 2020 12:22:49 BST, Paul Womack wrote:

>On Wed, 16 Sep 2020 at 09:13, Bruno Postle wrote:
>
>> It [TCA] would complicate the GUI, and stitching would take three times as
>> long. I'm not sure if there is demand now that some cameras do this
>> correction internally and it is available in all raw converters.
>>
>I think it would only increase the generation of the mapped images by three
>times. Stitching (enblending...), which is normally the slower process
>(at least for me) would be unaffected.

I'm not saying it couldn't be integrated if somebody really wanted it and did the work, but Hugin is quite complex already. I also seem to remember it has a different lens distortion model (possibly the lens model that panotools should have had in the first place).

--
Bruno