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Author Topic: Panorama distortion correction  (Read 1040 times)

mdijb

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Panorama distortion correction
« on: April 07, 2017, 04:28:00 PM »

When creating a panorama of an interior or other closeup subject, the distortion that  results  needs to be corrected.  I have watched videos using the Adaptaive wide angle fillter, but the result is hard to come by and not enough.

What methods dos the community use?  I s ther an easier way to do this

I have attached a sample image so you can see the distortion I am dealing with.

MDIJB
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BartvanderWolf

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Re: Panorama distortion correction
« Reply #1 on: April 07, 2017, 05:43:00 PM »

When creating a panorama of an interior or other closeup subject, the distortion that  results  needs to be corrected.  I have watched videos using the Adaptaive wide angle fillter, but the result is hard to come by and not enough.

What methods dos the community use?  I s ther an easier way to do this

I have attached a sample image so you can see the distortion I am dealing with.

Hi,

This would be relatively easy with a dedicated Pano stitching application. The 'ease' does depend on how the image tiles were shot, No-Parallax Point (NPP) rotation is preferred. However, converting this into a rectilinear projection would reveal that more image tiles would be required for full coverage in the top/bottom center area. Another option would be a flat plane projection conversion, but that would have required avoiding to get the foreground counter in the image (by using a higher vantage point).

Cheers,
Bart
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kers

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Re: Panorama distortion correction
« Reply #2 on: April 08, 2017, 05:42:49 AM »

As i see your photo it seems it is a cylindrical projection.
You cannot see it as distortion it is something natural.
Because this image has a view over 110  this is the only way to show it - a more normal rectilinear projection would stretcht the corners in a way you would not like it.
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TonyW

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Re: Panorama distortion correction
« Reply #3 on: April 08, 2017, 12:24:03 PM »

I agree with Bart much easier with a dedicated Pano stitching app, after first establishing the NPP and adding more images.

If the distortion was not so great you may be able to correct in PS.  As it stands there is IMO just to much pushing and pulling of pixels required and the interpolated results likely to be unsatisfactory unless viewed as relatively small images from a raw capture.

Still that has not stopped me having a very quick play, really out of curiosity.  Split the image in half and worked on each half separately using the warp tool.  With a little more careful work with the full size images, maybe, just maybe acceptable results until you can reshoot?
« Last Edit: April 08, 2017, 12:31:28 PM by TonyW »
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Rainer SLP

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Re: Panorama distortion correction
« Reply #4 on: April 08, 2017, 02:21:13 PM »

quote" after first establishing the NPP and adding more images. "

NPP = Nodal Projection Point ?
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TonyW

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Re: Panorama distortion correction
« Reply #5 on: April 08, 2017, 02:28:55 PM »

quote" after first establishing the NPP and adding more images. "

NPP = Nodal Projection Point ?
Sorry, Non Parallex Point
http://www.johnhpanos.com/epcalib.htm
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BartvanderWolf

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Re: Panorama distortion correction
« Reply #6 on: April 08, 2017, 02:30:01 PM »

quote" after first establishing the NPP and adding more images. "

NPP = Nodal Projection Point ?

No-Parallax Point (NPP), or rotation through the entrance pupil (not nodal point).

Cheers,
Bart
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BAB

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Re: Panorama distortion correction
« Reply #7 on: April 08, 2017, 03:09:00 PM »

When you use a really wide angle lens without the needed distance to subject you won't like the results. As mentioned more tiles are indeed called for but you will still need to be perfectly balanced and you need to know exactly where to start and where to end this also entails overlap calculations to take advantage of maximum width.
From your image it looks like your trying to include to much width for the depth you have to work with, my suggestion would be to move your human subject closer to the window light and limit the amount of window you include in the story there by shortening the length of the pano. You could also complicate things more by using movements, but the easiest way to shoot this pano is with a Sietz VR pano drive it will make all calculations and shoot all tiles perfectly. Also as said even with shooting more tiles no software can bend back the distortion you have caused by the wrong choices you have made knowing that before you create the image saves time and frustration.

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Rainer SLP

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Re: Panorama distortion correction
« Reply #8 on: April 08, 2017, 06:28:02 PM »

No-Parallax Point (NPP), or rotation through the entrance pupil (not nodal point).

Cheers,
Bart

Thanks
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Thanks and regards Rainer

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LesPalenik

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Re: Panorama distortion correction
« Reply #9 on: April 08, 2017, 10:12:27 PM »

As i see your photo it seems it is a cylindrical projection.
You cannot see it as distortion it is something natural.
Because this image has a view over 110  this is the only way to show it - a more normal rectilinear projection would stretcht the corners in a way you would not like it.

+1
That's why it is not easy to produce a pleasing looking panorama, especially indoors with ultra wide lenses. Some 270-360 degree interior panoramas look outright awful, but they depict truthfully the photographed scene. To minimize the distortion, try to use the longest possible focal length you can get away with.

BartvanderWolf

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Re: Panorama distortion correction
« Reply #10 on: April 09, 2017, 09:59:27 AM »

The more I look at this image, the more puzzled I get. It almost seems like the rear wall is not straight to begin with, it appears to be two walls that have a shallow angle at 3 columns of shelves from the left. Hard to say for sure though, since we do not have enough detail info, nor do we have enough/any tiles to work on.

The perceived distortion in purely due to the projection used, in combination with viewing the image from too far away (which is almost unavoidable with such a wide angle).

Cheers,
Bart
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mdijb

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Re: Panorama distortion correction
« Reply #11 on: April 09, 2017, 08:19:59 PM »

Wouls AutoPano or PTGUI so;vethis problem?

MDIJB
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BartvanderWolf

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Re: Panorama distortion correction
« Reply #12 on: April 10, 2017, 06:26:16 AM »

Would AutoPano or PTGUI solve this problem?

In my experience, PTGUI will give most control for solving such situations. It also offers several projection methods that can mitigate specific issues, and it allows to compress projection distortion a bit.

The rectangular Wall-rack structure allows defining horizontal and vertical control-points which should allow perfect automatic squaring up of the rear wall. If the image tiles have enough overlap, then lens distortions will also be correctable.

What will remain is the fact that the wide angle of view and short shooting distance (both are hard to avoid in the given example), will give a 'sense' of stretched corners. But that's hard to avoid (with a rectilinear projection on a flat plane) unless the image is viewed from a closer distance, printing large will kind of automatically allow doing that without too much discomfort.

Cheers,
Bart
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