Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Stitching Templates
Posted: 7 Feb 2010 at 11:02 GMT
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Please allow me to ask a question and forgive me if it seems incredibly stupid.
By the way I am using APG.
Ok, regarding templates - I shoot a scene which has good control point coverage - and by this I assume this means one that has numerous well positioned control points and then save this as a template. Fine, I get that part.
But if that scene is say, an exterior pano of buildings how will the distribution of control points in that scene help with the stitching of my next pano which may be an interior of a kitchen? What I mean is, every feature within the two scenes is going to be different, by the very nature that they are two different subjects. So, how will a template of scene 1 help stitch scene 2?
Wait a minute - I think the penny may have dropped!
Does it work because, in effect it does not matter what the content of the scene is, what is important is that the control points are there from the first scene and they help stitch any subsequent pano using the original template no matter what the content?
Or is this hopelessly wrong as well?
Hopefully, my lack of knowledge on this subject will elicit some responses from the experts out there and help others like me!
Also, if anybody has further tips re: control points or templates I am sure they would be very much appreciated by all.
Thanks again
Paul
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Hans Nyberg
Posts: 2760
Location: Denmark
Registered: 28 Aug 2005
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Re: Stitching Templates
Posted: 7 Feb 2010 at 13:03 GMT
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I have absolutely no idea how good Autopano works with templates, however with PTGui I am able to do fully automatic stitching using Batchbuilder and a template optimized for my Camera+lens setup.
The only thing you need to take care of is that you take the first image in your panorama perfectly leveled.
It is important to know how the stitcher works and how the different optimize parameters affect you image before you start working with templates as optimizing for all parameters can ruin the process for some panoramas.
To do a template that works for all kind of scenes you have to use a subject where you can set perfect controlpoints through the full 180 degree vertical blending area, This will give you a correct lenscorrection you can use for the template and you can then take another panorama which you just optimize for the positions yaw pitch and roll and not for the lens. When your lens is optimized you just need a few controlpoints and that means you can rely on the automatic controlpoint generator much better.
To do that you need to have a stitcher like PTGui where you have fully control of the process.
How good it works also depends on the lens you are using. 6+1 fullframe images are much easier to batchstitch than 4 Sigma 8mm images.
Hans
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Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Re: Stitching Templates
Posted: 7 Feb 2010 at 13:11 GMT
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Hi Hans,
Thank you. I am using a Sigma 8mm with a full frame chip canon.
Is the process for setting yaw pitch and roll crucial in achieving a perfect stitch?
Paul
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Tim Eastman
Posts: 171
Location:
Registered: 15 Nov 2006
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Re: Stitching Templates
Posted: 7 Feb 2010 at 13:39 GMT
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Another question relating to control points along a seam: they should be distributed evenly along the length of the seam from top to bottom ( I think ) Is it better that the seam is defined as the middle of the overlap region? Or just anywhere in the overlap region? The reason for these questions is I am thinking I could use my laser level / plumb to project a line along the exact " center " of the overlap and pick points along it. Of course this could be complete overkill!
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mediavets
Posts: 1948
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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Re: Stitching Templates
Posted: 7 Feb 2010 at 13:58 GMT
updated: 7 Feb 2010 at 14:06 GMT
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Paul Elton said: Please allow me to ask a question and forgive me if it seems incredibly stupid.
By the way I am using APG.
If you are using APG - as I do - then I suggest that in future you post questions about that software on the Autopano forum because most of the people here on Panoguide use PTGui.
Ok, regarding templates - I shoot a scene which has good control point coverage - and by this I assume this means one that has numerous well positioned control points and then save this as a template. Fine, I get that part.
But if that scene is say, an exterior pano of buildings how will the distribution of control points in that scene help with the stitching of my next pano which may be an interior of a kitchen? What I mean is, every feature within the two scenes is going to be different, by the very nature that they are two different subjects. So, how will a template of scene 1 help stitch scene 2?
Wait a minute - I think the penny may have dropped!
Does it work because, in effect it does not matter what the content of the scene is, what is important is that the control points are there from the first scene and they help stitch any subsequent pano using the original template no matter what the content?
Or is this hopelessly wrong as well?
Hopefully, my lack of knowledge on this subject will elicit some responses from the experts out there and help others like me!
Also, if anybody has further tips re: control points or templates I am sure they would be very much appreciated by all.
Thanks again
Paul
a) your understanding of the simple template feature in APP/APG is not correct. AFAIK an APP/APG template is really simply about supplying information about the relative positioning of the images in an image set which assists the stitcher when placing CPs because it then 'knows' which images are adajacnet to each other and can avoid placing inaccurate CPs on non adjacent images. The CPs as such are not used.
Hans' description of templates and their use relates solely to PTGui, and does not apply to APP/APG.
b) if you are shooting with a Sigma 8mm FE on a fullframe sensor Canon then the template feature in APG is really quite irrelevant IMO.
Why did you think you wanted/needed to use the template feature in APG?
Andrew
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mediavets
Posts: 1948
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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Re: Stitching Templates
Posted: 7 Feb 2010 at 14:04 GMT
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Tim Eastman said: Another question relating to control points along a seam: they should be distributed evenly along the length of the seam from top to bottom ( I think ) Is it better that the seam is defined as the middle of the overlap region? Or just anywhere in the overlap region? The reason for these questions is I am thinking I could use my laser level / plumb to project a line along the exact " center " of the overlap and pick points along it. Of course this could be complete overkill!
Are you using PTGui or APP/APG?
Andrew
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mediavets
Posts: 1948
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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Re: Stitching Templates
Posted: 7 Feb 2010 at 14:07 GMT
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Paul Elton said: Hi Hans,
Thank you. I am using a Sigma 8mm with a full frame chip canon.
Is the process for setting yaw pitch and roll crucial in achieving a perfect stitch?
Paul
Hans' comments relate to PTGui not to APG.
Andrew
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Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Re: Stitching Templates
Posted: 7 Feb 2010 at 14:21 GMT
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Hi Andrew,
Thanks for your reply.
So, are you saying that with my set up there is no advantage to using a template in APG?
If so why? I have been led to believe that this greatly speeds up the process.
Also, is it possible to tell APG Y P and R values? Does this help to achieve perfect stitching ?
Paul.
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mediavets
Posts: 1948
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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Re: Stitching Templates
Posted: 7 Feb 2010 at 14:27 GMT
updated: 7 Feb 2010 at 14:30 GMT
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Paul Elton said: Hi Andrew,
Thanks for your reply.
So, are you saying that with my set up there is no advantage to using a template in APG?
I don't think so. What is your shooting pattern 3 around plus Zenith and Nadir?
If so why? I have been led to believe that this greatly speeds up the process.
Where did you acquire this info? Was it in relation to APP/APG or PTGui?
Also, is it possible to tell APG Y P and R values?
Yes, but see next response.
Does this help to achieve perfect stitching ?
No - not normally. The only time I can envisage manually entering Y,P and R values for an image would be if APP/APG was unable to place any CPs to link an image in a pano; which is very unlikely ever to be the case if shooting with a Sigma 8mm FE on a fullframe sensor body.
Are you having problems getting good stitches?
Andrew
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Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Re: Stitching Templates
Posted: 7 Feb 2010 at 16:06 GMT
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Hi Andrew,
I am using a NNR10 and shooting 4 images with a +5 degree tilt for the Zenith. Not shooting Nadir image.
Not having horrendous problems but with my other pano head a Manfrotto 303SPH and using a canon 20mm lens, I was having problems achieving a very accurate NPP position - but that was probably down to me!
Hopefully, the R10 will help with this.
Seems as though you have cleared up some confusion for me though. In APG a good stitch being possible with auto/manual set control points.
Thanks again.
Paul
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Hans Nyberg
Posts: 2760
Location: Denmark
Registered: 28 Aug 2005
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Re: Stitching Templates
Posted: 7 Feb 2010 at 16:19 GMT
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The advantage of using a template (in Ptgui ) is that you can stitch panoramas perfectly even if they are of a kind that generate very few controlpoints.
For real estate panoramas this might often be the majority of of them if you live in a country with minimalistic furniture and white walls /ceilings or if you have to do non furniture apartments.
If your lens data is fixed in the template and if the stitcher can be set not to generate new settings you can still stitch based on very few controlpoints that place the images correctly for yaw-pitch and roll. In theory you just need 2 controlpoints per pair for that.
Hans
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mediavets
Posts: 1948
Location: Isleham, Cambs., United Kingdom
Registered: 8 Feb 2008
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Re: Stitching Templates
Posted: 7 Feb 2010 at 16:22 GMT
updated: 7 Feb 2010 at 16:22 GMT
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Paul Elton said: Hi Andrew,
I am using a NNR10 and shooting 4 images with a +5 degree tilt for the Zenith. Not shooting Nadir image.
Paul
You should have no problems at all stitching panos shot with this setup using APG.
Did you try 3 around rather than 4 around?
Hope to 'see' you on the Autopano forum, as well, sometime.
Are you using Autopano Tour?
Andrew
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Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Re: Stitching Templates
Posted: 7 Feb 2010 at 16:28 GMT
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Hi Andrew,
I have APT but have not used it yet. I thought I would try and understand APG first!
Currently I am using Pano2vr, do you have any experience of this program?
How does it compare to APT?
Paul
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Paul Elton
Posts: 43
Location: European Union
Registered: 28 Apr 2009
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Re: Stitching Templates
Posted: 7 Feb 2010 at 16:31 GMT
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Hi Hans,
Thank you for your reply. Slowly, I am beginning to understand!
I will be shooting the type of subjects that you suggest. Maybe PTGui is the way to go - which is a bit of a bummer as I have just invested in APG/APT!
Regards
Paul.
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John Houghton
Posts: 3412
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Stitching Templates
Posted: 7 Feb 2010 at 17:04 GMT
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Tim, Having your control points along the middle of the overlap region is useful, but not necessarily enough to guarantee a good stitch. It may give you one with invisible seams, but the stitch might still be poor.
Take a stitch of two back-to-back circular images. This configuration is unique for fisheye images in that they can be joined without parallax problems (with the correct panohead setup). The overlap is small, but you can get a good seamless stitch without any trouble by assigning a few control points in the small overlap area all around the edge of the images. The stitch will not, however, be very good as the optimizer will be unable to evaluate lens parameters to correct distortion over much of the image area. There are no control points there. Consequently, you can have severe distortion uncorrected in the final stitch. The images can be succesfully stitched by using a template that applies calibrated lens parameters to properly correct the lens distortions. As Hans says, when you have a template, you then need fewer control points and their positioning is much less important.
John
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