Go Back   Steve's Digicams Forums > Software > Panorama / Stitching

Reply
 
Thread Tools Search this Thread
Old Jul 15, 2009, 5:35 PM   #1
Junior Member
 
Join Date: Mar 2009
Posts: 1
Default People distorted (wide) in Panoramic

I have an Olympus SP-570OUZ. I set the camera for Panoramic, stitch with a computer. I used PTGui to stitch the photos and everything is great except the father people are from the center of the photo the wider they get. It's not a huge expansion but it is noticeable. I set up the group of 74 people in a straight double line and took four seperate photos for each panormic. I was thinkig that mybe I need to put them in an arc but buildings don't appear to have the problem so I figure there must be a setting that could correct the problem. Any help would be appreciated as the people near the edges of the photo are asking for me to do some adjusting.
Dragonflyoh is offline   Reply With Quote
Sponsored Links
Old Jul 16, 2009, 4:37 PM   #2
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

Most likely you are looking at projection distortion, though that should show the same effect for the buildings in the background. Could you post a downsized! and uncropped copy of the stitched photo? What stitching software did you use? Did it give a choice of projections?
BillDrew is offline   Reply With Quote
Old Jul 16, 2009, 5:54 PM   #3
Senior Member
 
dwig's Avatar
 
Join Date: Feb 2005
Posts: 133
Default

Quote:
Originally Posted by Dragonflyoh View Post
...I set up the group of 74 people in a straight double line and took four seperate photos for each panormic. I was thinkig that mybe I need to put them in an arc...
The only cure is to arrange the people in concentric arcs. When doing multiple shot stitched panoramas, as opposed to the antique swinging camera pano's (e.g. Circuit, Panon, ... cameras), you would also want to use the longest focal length lens and the corresponding highest number of images practical to reduce projection distortion on the individual images.
dwig is offline   Reply With Quote
Old Jul 16, 2009, 8:07 PM   #4
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

Try a horizontal cylinder projection if PTGui uses that nomenclature. Or try some different projections. There is probably one that will reduce that effect considerably.

You might download the free Microsoft ICE for something simple to experiment with. If you leave it on automatic for camera motion it will usually decide on a horizontal cylinder. You always have to crop when it is through even if you took a perfect panorama. And PTGui will probably do a more pronounced cylinder projection. ICE seems mild compared to others.
slipe is offline   Reply With Quote
Old Jul 16, 2009, 9:38 PM   #5
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

This is uncropped with a cylindrical projection. It is from 5 shots taken just before dark today with the camera held with the long side up. I was testing the ability of ICE to even out the exposures. It did a decent job as there was a large exposure and WB difference in the individual photos.

I compared it to some other projections and the ones that gave a rectangular result that didn’t need much cropping also seemed to fatten stuff on the outer part and gave a wider aspect ratio.

I tried PTGui and it will only do the panorama automatically in linear or fisheye. It does have a cylindrical projection but I got a message that it could not fix the points in other than linear or fisheye. I did get a message that I had stripped the EXIF, so that might have been the problem. I’ll play a little with it tomorrow. In the meantime you might want to try ICE. It is a free download from Microsoft. http://research.microsoft.com/en-us/...roups/ivm/ICE/ The help file just takes you to the forums, but it is pretty simple to use.

Edit: I know.......I'll cut the grass tomorrow before the neighbors complain.
Attached Images
 

Last edited by slipe; Jul 16, 2009 at 9:41 PM.
slipe is offline   Reply With Quote
Old Jul 20, 2009, 2:41 AM   #6
Member
 
Join Date: Jan 2006
Posts: 57
Default

Quote:
Originally Posted by slipe View Post
I tried PTGui and it will only do the panorama automatically in linear or fisheye. It does have a cylindrical projection but I got a message that it could not fix the points in other than linear or fisheye.
You can only generate control points automatically for LENS types rectilinear or fisheye. The output panorama can be generated in a wide variety of projections regardless of the lens type. The most common ones (including cylindrical) can be selected by a click on the appropriate icon in the Panoram Editor window, so they can be readily compared. In the case of the wide people, the cylindrical projection should solve the problem satisfactorily.
panostar is offline   Reply With Quote
Old Jul 20, 2009, 1:59 PM   #7
Senior Member
 
Reanimator's Avatar
 
Join Date: Nov 2005
Location: Huddersfield
Posts: 1,347
Default

you need a panoramic "nodal" mount, a camera need to revolve around the optimum point inside the lens, if your holding the camera and panning or on a tripod and panning the lens is moving an causing distortion, a nodal mount sets the camera back on the tripod so lens is over the mounting point......hard to explain but if u search online for " nodal point" it may show u
am making a mount for my cam as they are hellishly expensive
Reanimator is offline   Reply With Quote
Old Jul 20, 2009, 9:19 PM   #8
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

IMHO the need for nodal point rotation is much overstated. In particular, if you are using one of the Panorama Tools based programs (PTGui is a good one), being able to fine tune the stitch "line" so it goes in some harmless place instead of the middle of a face deals with most of that problem.

It is well worth figuring out why you want to rotate about a nodal point, and to experiment with deliberate failures to do so. There is a limit to how far off you can be which depends on distance, subject, stitching software, phase of the moon, ... Try stuff and figure out what works for you.
BillDrew is offline   Reply With Quote
Old Jul 22, 2009, 1:59 PM   #9
Junior Member
 
Join Date: Jul 2009
Posts: 6
Default People distorted (wide) in Panoramic

I read all of the responses and want to thank everyone for their thoughts. I did a couple of things. I downloaded ICE and it did a great job of getting everyone from the original photos slimmed down. I then took a practice shot of some people that I spread out and had move for every shot but placed them in an arc. I then used the Olympus software that I used in the original photo and the results were good, no width distortion. I then used PTGui and the results were excellent. I then used ICE and again the results were excellent. I also took a practice photo with everyone in a straight line and used PTGui with the setting of cylindrical projection and the results were excellent. ICE also did a great job. I used the Olympus software and the wide people appered. My conclusion is that the Olympus software is the culprit. I was using version 2.2.
I now need to get some experimenting with PTGui. Panoramic photos are fun!
Again, thanks for all of the help!
Dragonflyoh2 is offline   Reply With Quote
Old Jul 23, 2009, 8:16 AM   #10
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

Quote:
Originally Posted by Dragonflyoh2 View Post
...
I now need to get some experimenting with PTGui. Panoramic photos are fun!
Again, thanks for all of the help!
I'd recomend that you figure out how to define the stitch lines yourself instead of letting the program do it. That will let you fix/hide all kinds of problems. Also try some off level panos and figure out how to deal with those. Like most things, both are easy once you figure out how to do them.

I think you will also find that PTGui is also great for doing things like getting rid of "perspective distortion" that happens when the plane of the sensor is not parallel to the subject - most noticeable in architectural photos. It will also help in aligning multiple shots of groups so you can clone heads, eyes, ... to fix the problem of someone having their eyes shut or some odd expression in one frame.
BillDrew is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 6:54 PM.