Skridlov
Posts: 164
Location: United Kingdom
Registered: 12 Nov 2007
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Barrel distortion in cylindrical panoramas
Posted: 11 Nov 2008 at 18:11 GMT
updated: 11 Nov 2008 at 18:11 GMT
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I have been working up some external panoramas of the buildings in which I have done sphericals. One problem that I notice repeatedly is that there is always a pronounced curvature to horizontal elements above (and presumably below, in theory) the vertical pov of the shots. Typically these are taken using a 17 mm lens in portrait format (X 1.5 on a Nikon DX body) which itself exhibits a fair amount of barrel distortion. There are usually four to six shots in each sequence.
I have done quite a lot of experimentation without any real improvement. If I remember correctly there is always going to be curvature in panoramas of this kind. But is there anything that can be done to minimise the effect?
Roy
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mediavets
Posts: 534
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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John Houghton
Posts: 2335
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Barrel distortion in cylindrical panoramas
Posted: 11 Nov 2008 at 20:15 GMT
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Roy, The curvature that you are getting with wide cylindrical projections is predictable and inevitable. The problem has been raised many times before, both here and in other forums. Ways around the the problem include distorting selected areas using Photoshop's transform tools; generate a number of carefully chosen rectilinear views and join them together; use the utility from www.altostorm.com/ . Some subjects are more amenable to correction than others. The barrel distortion in the input images is irrelevant as that is corrected by PTGui or other stitching software.
John
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Ken Warner
Posts: 377
Location: Mammoth Lakes, United States
Registered: 14 Aug 2004
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Re: Barrel distortion in cylindrical panoramas
Posted: 11 Nov 2008 at 23:11 GMT
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Do you have an example image that I could try something
with?
email me offline and I'll explain.
kwarner000@verizon.net
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