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Author Topic: More squashy architecture problems  (Read 1765 times)

sharperstill

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More squashy architecture problems
« on: March 13, 2019, 11:41:00 pm »

Hi all,
I'm back with another shifted-n-stitched nightmare.
I had to do this scene from both angles and needed to shoot a stitch sequence in order to get the width without having power poles in front of me.
In the first I was near the edge of the scene and it has worked out ok.
In the second, shown here, I am in a position opposite what will be the entryway to a new building that is incorporating the heritage buildings in this scene. The architectural renderers are going to put their render of the proposed new building into this scene picture.
It was shot with camera in vertical orientation, 17 mm shifted some (can't remember how much but not heaps) - 3 images.
So first image is how it stands in PTGui Pro - the optimiser is reporting "very good". I have chosen 'rectilinear' projection. My main concern is the volumetric distortion on the town hall building and clock tower.
The next screen shots show the image after some work in the 'adaptive wide angle filter' in P'shop (where the upper right walk sign is still largely circular) and then again after a run through 'lens correction filter' (where the upper right walk sign has become elliptical). In the former the building volume looks more correct but the whole row of buildings looks to be curving away from the camera too much. In the latter the plane has flattened out to the expense of the building volume.
I'd love it if any had any ideas on how to improve this image.

Jon
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Bart_van_der_Wolf

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Re: More squashy architecture problems
« Reply #1 on: March 14, 2019, 10:33:46 am »

[...] I'd love it if any had any ideas on how to improve this image.

Hi Jon,

Looking at the first attachment, and I'm not familiar with the actual scene, it looks like the Pitch parameter for the Panostitch was not correct, which resulted in a curved horizon. That's easy to fix by either visually dragging the center of the pano in the Tools>Panorama Editor (CTRL+E)  down a bit in "Edit Panorama mode" from the toolbar selected, or by manually entering a pitch offset in the Numerical Transform dialog field in the editor (each click adjusts by the specified amount).

To automate the process, one can add multiple vertical control points, if the image has such, before optimizing.

Having a projection distortionless starting point will reduce the amount of postprocessing (warping) to get the visual effect that's required. I find Affinity Photo's tools for warping very good, but I know Photoshop also has several tools for that (even Lightroom has an automatic  UpRight function for it, if I'm not mistaken, but that can be hit or miss).

But it's best to get the Stitching part closer to where you want to go.

Cheers,
Bart
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kers

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Re: More squashy architecture problems
« Reply #2 on: March 14, 2019, 11:40:15 am »

I am afraid the angle is just too wide for rectilineair, you will have to leave the horizontal zebra...and turn to the right or cut the edges.
The problems you have are basic ; there is a limit to a 'normal' looking rectilineair image.
(Depending on personal taste )
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Craig Magee

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Re: More squashy architecture problems
« Reply #3 on: March 20, 2019, 03:29:47 pm »

That looks really weird for a flat stitch, looks more like a rotational one that's been set to rectilinear projection.
What are you telling ptgui it's working with?
Have you tried Photoshop, specifically picking perspective as a stitch mode and making sure you turn off correct geometric distortion.


« Last Edit: March 20, 2019, 03:41:21 pm by Craig Magee »
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LesPalenik

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Re: More squashy architecture problems
« Reply #4 on: March 20, 2019, 07:33:28 pm »

It was shot with camera in vertical orientation, 17 mm shifted some (can't remember how much but not heaps) - 3 images.

The first version is not too bad. Fill in the black spots on the top with the Content Aware Fill, crop on the bottom, and you'll have an acceptable image.

If you can get a 20mm lens, I'm sure you would get a better result, even if you'll have to take 4 images instead of 3.

sharperstill

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Re: More squashy architecture problems
« Reply #5 on: March 21, 2019, 12:12:40 am »

That looks really weird for a flat stitch, looks more like a rotational one that's been set to rectilinear projection.
What are you telling ptgui it's working with?
Have you tried Photoshop, specifically picking perspective as a stitch mode and making sure you turn off correct geometric distortion.

Hi Craig, you're right I shouldn't have called it shift-n-stitch as it was a rotational pano. Not sure why I did that.
I didn't try Photoshop and it's all a bit moot now as the architects didn't want a composite so I borrowed a 14mm and re-shot.
Thanks for the reply though.

Jon
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Craig Magee

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Re: More squashy architecture problems
« Reply #6 on: April 01, 2019, 03:51:00 pm »

Hi Craig, you're right I shouldn't have called it shift-n-stitch as it was a rotational pano. Not sure why I did that.
I didn't try Photoshop and it's all a bit moot now as the architects didn't want a composite so I borrowed a 14mm and re-shot.
Thanks for the reply though.

Jon

Ah ok, yeah totally what I'd expect then. Interestingly I find multi-row shots with longer lenses tend to work better for rectilinear projections. Rather than a single row with a wide lens.

Fair enough though :)
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bwana

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Re: More squashy architecture problems
« Reply #7 on: April 02, 2019, 10:18:43 am »

can you 'shop' the third image by 'pinch' distortion in the middle? Lightroom has the distortion slider as well near the bottom of the 'Develop' pane
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Bart_van_der_Wolf

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Re: More squashy architecture problems
« Reply #8 on: April 02, 2019, 10:53:52 am »

can you 'shop' the third image by 'pinch' distortion in the middle? Lightroom has the distortion slider as well near the bottom of the 'Develop' pane

Or use a different geometric projection in PTGUI (which uses higher quality resampling than PS). One can even automate the 'distortion' correction by setting several horizontal (and perhaps a few vertical) controlpoints. Mind you, the apparent distortion is only due to having to view the image from the wrong (to far away) distance.
 
Cheers,
Bart
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