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Author Topic: Virtual viewpoint stitching woes  (Read 3062 times)

feppe

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Virtual viewpoint stitching woes
« on: October 26, 2011, 02:35:52 PM »

On a whim I tried virtual viewpoint shooting in NYC for the first time on a very NYC building. Since I didn't have a wide angle lens at hand (B&H closed for the entire week I was there :'( ), I shot two frames with a normal lens, moved the camera 5 meters and shot another column, moved the camera again for the third column. After quite a bit of fiddling in PTGUI, I've managed to get a result which at least looks like a building: 2 rows by 3 viewpoints result attached - I have further brackets, this is the 15 sec exposure.

I still can't fix the leaning building and skewed horizontals and verticals, though. Any help would be very welcome!

wolfnowl

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Re: Virtual viewpoint stitching woes
« Reply #1 on: October 26, 2011, 04:23:02 PM »

I don't know about PTGui but in Autopano Pro there's a 'verticals' tool where one can place markers at different places to show vertical surfaces.  In CS5 you could try Puppet Warp.

Mike.
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AFairley

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Re: Virtual viewpoint stitching woes
« Reply #2 on: October 26, 2011, 07:02:42 PM »

I don't know about PTGui but in Autopano Pro there's a 'verticals' tool where one can place markers at different places to show vertical surfaces.  In CS5 you could try Puppet Warp.

Mike.

Or you might be able to fix in CS5 just using the keystoning slider in the lens distortion filter, with the right amount of rotation..
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BernardLanguillier

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Re: Virtual viewpoint stitching woes
« Reply #3 on: October 27, 2011, 12:46:45 AM »

I still can't fix the leaning building and skewed horizontals and verticals, though. Any help would be very welcome!

You can define vertical and horizontal constraining control points with PTgui.

Just go to the control point tab, select the same image in the left and right views then select vertical of horizontal as control point type.

For vertical control points, create a control point by clicking on a vertical line of the building in the left window, and on a lower point of the same vertical in the right window.

Do that both on an image at the extreme left of the pano, and do the same to another one at the extreme right of the pano.

You can do the same for horizontal lines.

Then optimize once more (approve the proposal to change something)... and you should be done.

Cheers,
Bernard
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Oldfox

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Re: Virtual viewpoint stitching woes
« Reply #4 on: October 29, 2011, 01:25:59 PM »

moved the camera 5 meters
You should shoot all the images from very same spot, not move the camera. Ptgui can correct the verticals and horizontals as described.

Btw, if you stand too close to the building the result can look artificial. Also you may want to try different projections.

http://www.kivikukkula.com/photos/panos/hotel/3.htm

/fox
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feppe

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Re: Virtual viewpoint stitching woes
« Reply #5 on: October 29, 2011, 02:52:02 PM »

You should shoot all the images from very same spot, not move the camera. Ptgui can correct the verticals and horizontals as described.

I'm very familiar with regular stitching, but this is not about that. I'm talking about virtual viewpoint stitching, which should be clear from the thread title.

BartvanderWolf

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Re: Virtual viewpoint stitching woes
« Reply #6 on: October 29, 2011, 04:55:54 PM »

I still can't fix the leaning building and skewed horizontals and verticals, though. Any help would be very welcome!

Hi Harri,

Just add some 'vertical' controlpoints, and you'll be fine. Applications such as PTGUI allow to do that. There are special control points for use on vertical or horizontal features.

Cheers,
Bart
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kirkt

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Re: Virtual viewpoint stitching woes
« Reply #7 on: October 29, 2011, 11:59:43 PM »

The Distort, Puppet Warp and Lens correction tools should get you close enough.  Here is 5 minutes plus some very special recreated cityscape with the Content-Aware fill.  ;D

With the pano image you posted, expand your canvas first, then use distort to remap you image.  THen make tweaks to remove curvature, scale to restore proportion, etc.

Kirk
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Oldfox

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Re: Virtual viewpoint stitching woes
« Reply #8 on: November 01, 2011, 05:59:30 AM »

I'm very familiar with regular stitching, but this is not about that. I'm talking about virtual viewpoint stitching, which should be clear from the thread title.
Sorry, the term was unfamiliar to me. I've used Ptgui since 2002, so I should have known better. Maybe I should upgrade my version of Ptgui ;-)

But may I ask, why do you want to use 'virtual viewpoint stiching' in your picture? Wouldn't normal stiching be ok?

/fox

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