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Thread: Top stitch ok, bottom ok, but not together?

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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Top stitch ok, bottom ok, but not together?
Posted: 20 Apr 2012 at 6:47 GMT
I have a strange problem with a equiretagular I shot in a tight space. Using PTGUI PRO 9.0, Canon 5D and Canon 15mm fisheye I shot a top, bottom, nadir, and a series of 6 at 45 degrees up, and another 6 at 45 degrees down. I have shot other panoramas like this and did not have many problems stitching them.

But this time I cannot get the top and bottom to stitch together. If I run the top, and then the 6 45 degree up pictures, they stitch flawlessly without needing extra control points. Same with the bottoms plus the down and nadir. However when they are all together it wont stitch together right at all. Is there any extra settings or something I can set that might smooth things out?
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 20 Apr 2012 at 6:53 GMT
www.flickr.com/photos/avotius/sets/72157629493596... here is the resized jpgs of what I am trying to stitch.
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DorinDXN

Posts: 3116
Location: Timisoara, Romania
Registered: 14 Nov 2006
Re: Top stitch ok, bottom ok, but not together?
Posted: 20 Apr 2012 at 7:42 GMT
updated: 20 Apr 2012 at 7:45 GMT
Not able to see your photos.

There could be several causes, deppending on your pano head/setup you can have parallax error up-down, that is one to start with, or simply you need better lens parameters in PTgui.

cheers,
Dorin
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Hans Nyberg

Posts: 2874
Location: Denmark
Registered: 28 Aug 2005
Re: Top stitch ok, bottom ok, but not together?
Posted: 20 Apr 2012 at 9:47 GMT
updated: 20 Apr 2012 at 9:48 GMT
Shooting 6 up and down at 45 degrees with your camera and lens is a very bad and weird way of using it.

Most important the 45 degree down will have al lot of panohead in the image and that is bad unless you mask it out on all images.
It will attract automatic controlpioints which can completely destroy the optimizing.

Always avoid to have the panohead in the images.
If you shoot 10 degrees down you have everything included down to the rotator (If you use a NodalNinja or other head at similar size.)

You do not need more than 1 up at 60-70 degrees or 90 degrees.
Only if you have some very detailed objects like mosaic windows high up it can be an advantage to shoot 3 at 45 degrees.

The missing part at the nadir is now very small and you can easy take that by moving the tripod around 70-80cm and lean it over the original centerpoint.

I do not even tilt down but I take the nadir with the camera at same -10 degrees as the 6 around. That means that the nadir becomes an extension of the 6 around and has the same quality.

When you learnt this technic you can take the nadir in less than 30 sec and with a little help of a self standing monopod as pointer you can even take the nadir in the exact NPP making it possible to do 3D nadirs and even do batch stitching with the nadir included.

This is an example of 6 panoramas which was batch stitched completely automatic with the nadir included. 5D markII + Canon 15mm
panoramas.dk/panorama/batch-stitching-nadir/

Hans
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DennisS

Posts: 1787
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: Top stitch ok, bottom ok, but not together?
Posted: 20 Apr 2012 at 17:45 GMT
Your link requires a log in. Any other place you can post your pictures?
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 22 Apr 2012 at 14:45 GMT
Hey, sorry I stuck the photos in my flickr and forgot to change the permissions. I still cant get the images to stitch right. Its very strange, but then again it seems I didn't do this one right even though others I have shot like this have connected fine. Maybe I am over thinking my shooting?
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DennisS

Posts: 1787
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: Top stitch ok, bottom ok, but not together?
Posted: 22 Apr 2012 at 16:22 GMT
Colin,

Let me start by saying that I have little experience stitching multi row panos like this. I usually take 6 around plus Zenith plus Nadir or 4 around at 5 degrees plus hand held Nadir. Others with more experience will be able to fill in the details I have missed.

www.dlsphoto.net/Panoguide/10301.74993.zip

I was able to get the maximum error down to 2 by removing the Zenith and Nadir shots, removing one of the duplicate images taken at a different tilt, adding some vertical control points to the bottom row and removing control points from images that are not right next to or on top of each other. The stitch still has a couple of very small errors that can be dealt with in Photoshop.

Dennis
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Bob Stone

Posts: 387
Location: Rochester, NY, United States
Registered: 20 Oct 2007
Re: Top stitch ok, bottom ok, but not together?
Posted: 22 Apr 2012 at 16:51 GMT
Colin,
How did you shoot the nadir shots. IMG_3440 and IMG_3443 look like the same orientation but the tripod is moved. Were you intending to shoot two nadirs @ 180°? are you using the nadir adapter from nn?

You should shoot 6 around (one row) at 0° plus zenith and nadir with your setup, from vrwave.com:

Canon EF 15mm f/2.8 Fisheye
Recommended (full-frame): N, 6 images every 60° at 0°, Z
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John Houghton

Posts: 3934
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
Re: Top stitch ok, bottom ok, but not together?
Posted: 22 Apr 2012 at 20:21 GMT
Colin, I managed to get an excellent stitch using all of the images:

www.johnhpanos.com/colin.zip (2.7MB)

This contains the project file and equirectangular image (plus all the camera images with weird Flickr names). The ceiling beams were difficult to align exactly and I used some temporary t3,t4,t5 points with the PanoTools optimizer to help with this. The Final optimization gave figures of av: 0.8; Max: 2.8.

John
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 5:13 GMT
I really appreciate the help you guys are giving me. I am pretty new to this and I will change my shooting method as recommended to a 6@60 degree. Still learning this PTGUI program, only been on it for a couple months now.

I am using a cheapo Chinese made pano head as I could not find a nodal ninja here. I have one of these www.flickr.com/groups/panoramas/discuss/721576276... On my next trip back stateside I will look for one as they seem to be quite popular.

I am trying to understand what you guys did to the panorama to get it stitched right but I cant seem to get the same results with the full sized images. I put the original jpgs here www.flickr.com/photos/avotius/sets/72157629879609... Does size of the original images effect the stitching results?

Also John, what does "I used some temporary t3,t4,t5 points with the PanoTools optimizer" this mean? Is there a plug in or something that I can use here?
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 5:54 GMT
Also another maybe stupid question. I used a ret. full frame fish eye, but in PTGUI it always pops up as a circular. Does this make a big difference?
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 6:44 GMT
Still working on this one trying to figure out what I am doing wrong.

It seems when I am stitching it together I cannot get the sofa and two chairs around it to come together right, they always look very distorted where one arm will show twice.

Also I noticed from your two project files that mine have two or three times more control points.
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DorinDXN

Posts: 3116
Location: Timisoara, Romania
Registered: 14 Nov 2006
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 8:19 GMT
updated: 23 Apr 2012 at 8:21 GMT
Hi Colin, you're perfectly right, once the panohead is properly set up is all about control points, add them manually if they are in short supply and not as widely spread as those from John, then save the lens parameters or made a template for later use, using that template you will not need so many control points, nor to optimise again all the lens params, only y,p,r (yaw, pitch, roll) may be enough to have good stitch next time.

Dorin
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John Houghton

Posts: 3934
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 8:44 GMT
Colin, Here's the full size project and equirectangular image:

www.johnhpanos.com/colin-fullsize.zip (2.3MB)

(BTW, it does help a lot if you parcel multiple files in a zip or rar archive file. Downloading individual files is tedious. I use 7-Zip on a PC).

Blending is a problem. It looks like you might have used auto white balance. And the ceiling is a different exposure too. I adjusted the ceiling shot in Photoshop to match better with the other images. If you shot RAW, maybe you converted with auto white balance set.

Things generally align well without the ceiling shot, but I included it and used most of it with a green mask. The optimization is certainly worse for some reason when the ceiling shot is included, but the bland surface is largely devoid of features for control points where one would like to have them.

Provided control points are well spread out, you don't need huge numbers of points. I didn't use the line points (t3,t4,t5....) this time. They are not supported by the PTGui optimizer, so you have to use the Panorama Tools optimizer, which is available from the PTGui web site. You put control points along features that should be rendered straight in the output panorama. This usually means using rectilinear projection. A trick I sometimes adopt is to switch the output to a 100x100 degree rectilinear image, with (in this case) the ceiling brought into view using the numerical transform option or dragging. The beams across the ceiling ought then to be straight, and line points along the edges of the featureless edges of the beam can be used to force the edges in different images to align. (t3 points are used along one edge, t4 points along another edge, etc). Having optimized ok you can then restore the ouput image projection to equirectangular and to its correct orientation, remove the line points - which now won't work in equirectangular projection - and then leave the lens parameters alone (since they have been evaluated to align the images properly, including the zenith). The image can be levelled with some t1 points without disturbing the alignment of the images with each other.

Another thing to watch: don't use aperture f/22. It will give less sharp images than f/8 or f/11, which still have adequate depth of field.

John
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Colin Jones

Posts: 8
Location: China
Registered: 20 Apr 2012
Re: Top stitch ok, bottom ok, but not together?
Posted: 23 Apr 2012 at 9:12 GMT
I have been fumbling with this image for several days now but I am happy to say that I did get it just a moment ago. Now I see that John also came up with a good solution for the pictures.

I looked closely at how your project files were put together. At first I took the two rows of 6 and stitched them without a Z or a N and they went together great. Then I added the N shot where I moved the tripod to get the floor and added about 10 control points and it slotted into the floor perfectly. Here is what I ended up with www.flickr.com/photos/avotius/6959416558/in/set-7...

So it would seem I have been over thinking my panoramas. I need to learn a lot more about this stuff. I will do some more practicing with my head and see what I can come up with. There are a lot of old streets around here I would like to take pictures of.

I cant thank you guys enough for the help. If you were all around I would owe you a few rounds of Guinness.
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