Hugin making spiral panorama

[Graham Jantz]

Hi all, looking for some advice on running Hugin. I have a panorama of 83 photos that I'm trying to stitch together but the resulting image it's giving me is a weird spiral shape. I used the assistant and went through adding control points to images the did not have them and this still came out.

Also don't love that it tried to color correct some of the images. 

Sorry if this has been addressed before, new to Hugin.

[David W. Jones]

Hmm, sorry, a little hard for me to tell what it's supposed to look like. I assume the images with trees are supposed to be the ground, therefore should be horizontal. So maybe try adding horizontal control points to the tree images. Then try aligning again.

Then I'd try running Hugin's CPFind (prealigned) option. That only looks for control points between adjacent images. The spiral you're getting might be happening because there are control points between images that shouldn't be there. Clean control points (right-click Control Points > Clean control points) might help with that.

The Assistant always runs photometric correction. That might be why the colors are off. You can remove the photometric correction by going to the Photos tab, right-clicking in a blank area of the list, then clicking on Reset > Reset photometric parameters.

If none of that helps, I'd start from scratch, and do it manually if you hadn't done that before. I'd add horizontal control points first, then run the CPfind (prealigned) option. Then run the geometric optimization starting with the basic Positions (incremental, starting from anchor), then clean control points. Then run the next geometric optimization on the list and clean control points again. Stop when you finish the Everything without translation step.

Then check and see how the image looks.

Failing that, if you can share your photos somewhere, someone might be able to look at it. I won't be able to do that for a couple of weeks, unfortunately.

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[Greg 'groggy' Lehey]

On Monday, 19 February 2024 at 14:08:36 -0800, Graham Jantz wrote:
> Hi all, looking for some advice on running Hugin. I have a panorama of 83
> photos that I'm trying to stitch together but the resulting image it's
> giving me is a weird spiral shape. I used the assistant and went through
> adding control points to images the did not have them and this still came
> out.

Occasionally I get something like this, for reasons that I can't
understand.

My workaround, which works in 99% of the cases: start with a very few
images and align them in the fast panorama preview window. If the
partial result is good, save the .pto file. Add another couple of
images, align again. Save. Continue until all images have been
aligned.

This is possibly not perfect. I've recently become aware of the
--linearmatch option to cpfind. The man page is vague, but my
understanding is that this causes cpfind to search for control points
only in adjacent images. That might solve the problem, but it won't
work for multi-row panoramas.

> Also don't love that it tried to color correct some of the images.

This problem might go away by itself once the images are correctly
aligned. But you can tell Hugin not to change the colours.

Greg
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[Graham Jantz]

Thanks for the tips. I was able to make some progress but it's not yet where I want it to be. I find it's trying to make control points between images that are far away from one another and I think that's what caused the spiral. Here's what I've got so far but there's still another layer at the top that I haven't been able to get to line up. Also there's still lots of misaligned images.

[Greg 'groggy' Lehey]

[Rearranged for clarity]

On Tuesday, 20 February 2024 at 7:55:43 -0800, Graham Jantz wrote:
> On Monday, February 19, 2024 at 6:06:07 PM UTC-7 Groogle wrote:
>> My workaround, which works in 99% of the cases: start with a very few
>> images and align them in the fast panorama preview window. If the
>> partial result is good, save the .pto file. Add another couple of
>> images, align again. Save. Continue until all images have been
>> aligned.
>>
>> This is possibly not perfect. I've recently become aware of the
>> --linearmatch option to cpfind. The man page is vague, but my
>> understanding is that this causes cpfind to search for control points
>> only in adjacent images. That might solve the problem, but it won't
>> work for multi-row panoramas.
>

> Thanks for the tips. I was able to make some progress but it's not
> yet where I want it to be. I find it's trying to make control points
> between images that are far away from one another and I think that's
> what caused the spiral.

Yes, this is what I expected. That's why I suggested just a few
points to start with. Is that what you did?

> Here's what I've got so far but there's still another layer at
> the top that I haven't been able to get to line up. Also there's still lots
> of misaligned images.[image: DSC_0070 - DSC_0131_resize.png]

This suggests that you at least just did one row. Without knowing
what the original looks like, it's not clear how good this pano is.

What you could do, which would also solve the --linearmatch issue, is
to create single row panos and then stitch them together.