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Thread: Stretch factor in spherical panoramas

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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Stretch factor in spherical panoramas
Posted: 27 Sep 2012 at 19:30 GMT
Hello everyone. I am having a few customers complain about the "stretch" or "warp" at the screen edges when you revolve a sphehrical pano. How do I reduce or eliminate this effect? My rig is a Nikon d5000 w/ Sigma 8mm f/3.5 on a NN4. Here is a link to a project that illustrates my concerns. Please use the drop down at top right of the pano and select Double Room. Thanks in advance for your help.

Marriott Grand National: www.vpix.net/index.php?tour=101313
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DennisS

Posts: 1758
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: Stretch factor in spherical panoramas
Posted: 27 Sep 2012 at 20:14 GMT
Limit the amount the user can zoom out.

I limit zooming out (in order to control "stretch or warp") and zooming in (in order to control pixilation).

Your initial view when the panorama opens may be zoomed out too far.
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 27 Sep 2012 at 20:40 GMT
Thanks for the speedy reply Dennis. Unfortunately my tour building software, VPiX, doesn't allow me to limit the ranges on zooming in or out. I am readying myself to learn Flashificator, which I presume will allow me to do limiting. I was wondering if my equipment, specifically my lens, is causing this to occur. Would a 10-17 or 10-24 lens lessen the effect? I realize it means more shots but I would opt for it if my quality would benefit.
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Flashificator

Posts: 147
Location: Lima, Peru
Registered: 16 May 2012
Re: Stretch factor in spherical panoramas
Posted: 27 Sep 2012 at 21:18 GMT
This issue is - as Denis has stated - due to the zoom level applied. The issue could even be worse if the zoom level is set to be far out and the pano is viewed on a large monitor.

Changing lenses on your camera will not help solving this at all. More shots for a panorama with a narrower lens will provide you with access to more visual quality options, but change nothing regarding the player setup.

Trausti
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Flashificator - User examples
flashificator.com/gallery.htm
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 2:33 GMT
Thanks to both of you for your replies. As I am very limited in my control of certain tour building functionality with my current pano building gui, I will be switching to Flashificator in the next few weeks. Of course you will most likely see more posts for assistance following my purchase. Specifically about mobile viewing, that looks like how most people will access our product/art.
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hindenhaag

Posts: 900
Location: Netherlands
Registered: 7 Mar 2010
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 11:54 GMT
Hi,

I had a look to your double room. I understand your customer is complaining.

The picture is not even leveled in horizon besides the other effects.

It would be nice to test your set of pics. Can you send the set of pics for double room for example with www.ge.tt . You may send it via IM as well. I'd like to ply around with lens correction etc. in PS for example or DxO.

I have a D5100 and the Sigma to make some test shots.

Kind Regards,
Heinz
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DennisS

Posts: 1758
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 12:32 GMT
I also took a look at the double room.

When you shoot small rooms it is critical that you get the camera at the correct height. The first thing I did was to pan down to get a better view of the beds. This forces all the verticals to lean outward.

If you drop the camera down lower, the viewer will tend to pan around without panning down. I like to put the camera at the midpoint of a doorway. When you pan around you get equal parts ceiling and floor. Makes for a balanced view. The lobby panorama looks nice because it is such a big room. In bigger rooms you can raise the camera higher.

You also need to level this panorama.

Small rooms accentuate shooting and stitching errors.

If you cannot limit your viewing parameters, time to move on to new software.
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OrmarT

Posts: 111
Location: Tallinn, Estonia
Registered: 11 Mar 2006
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 14:18 GMT
You have now fovmin="45" fovmax="135" It's krpano after all.
Sure, you can change those numbers, if the tour is in your server.
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 14:54 GMT
Hello Heinz, thanks for your desire to look into this situation. I have corrected the leveling and found a way to zoom in a bit.

Here are the zipped images from the camera via Lightroom: ge.tt/46UtYXO/v/0?c

PTGui project file is here: ge.tt/3r5vwXO/v/0?c
Pano in psd format is here: ge.tt/6nzxwXO/v/0?c
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hindenhaag

Posts: 900
Location: Netherlands
Registered: 7 Mar 2010
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:01 GMT
Thx for your upload.

I'll check it this weekend with different software. Did you use lens correction in Lightroom?

So long,
Heinz
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:05 GMT
Ahhh, I see. Thanks for the tip. I'll write "midpoint of doorway" on my pre-flight checklist. As for leveling, do you mean assigning more vertical CPs in PTGui? Or simply adjusting my start point in VPiX? I agree about the software. I'll spend this weekend reviewing my options, feel free to plug your favorite. Thanks Dennis for your time and advice.
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:06 GMT
Thank you very much. No lens correction was applied.

Trey
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hindenhaag

Posts: 900
Location: Netherlands
Registered: 7 Mar 2010
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:09 GMT
updated: 28 Sep 2012 at 15:19 GMT
You are really quick.. wink

I'll let you know how to level easily in PTGui.

You can download trial versions to test different software. Helps to decide.

Check the use on mobile phones as well.

Cheers,
Heinz
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treygaf

Posts: 10
Location: United States
Registered: 27 Sep 2012
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:10 GMT
VPiX is a GUI for krpano. So I have to use what they provide as far as manipulating outcomes. Like Dennis stated, "time for new software". BTW, how did you find those settings in the pano?

Thanks for your time,
Trey
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hindenhaag

Posts: 900
Location: Netherlands
Registered: 7 Mar 2010
Re: Stretch factor in spherical panoramas
Posted: 28 Sep 2012 at 15:28 GMT
I got information about new DxO Software:

www.dxo.com/us/photo/dxo_viewpoint/introduction

You can download a trial and test it.

Heinz
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