dracula
Posts: 2
Location: Donji Miholjac, Croatia
Registered: 26 Jun 2012
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Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 14:40 GMT
updated: 26 Jun 2012 at 14:42 GMT
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Hi everyone,have couple of questions that bothers me 
If i try stitching images without zenith i get almost excellent result (Average CP: 0,55, Max CP:1,21) and no stitching errors.
When i use zenith image also i get (Average CP: 3,8, Max CP:10,86) and lot of stitching errors on top of the panorama.
Optimized using Heavy + lens shift
Also i noticed that on exterior panos with grass when i use zenith i get some wierd ghosting overy 90° like in screenshot
I'm using ptgui 9.1, images are taken with Nikon D200, Samyang 8mm and NN5
Testing minimum paralax i got my best at URS at 95.5mm and LRS at 63mm
Images of first pano.zip were taken every 60° at -15° and one zenith and 90°.
Images of second pano2.zip were taken every 90° at 0° and one at 90°
Here are links to images if someone woul like to try:
www.fkdm.hr/pano/pano.zip (problems with stitching errors)
www.fkdm.hr/pano/pano2.zip (problems with ghosting)
Tnx for help
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Hans Nyberg
Posts: 2871
Location: Denmark
Registered: 28 Aug 2005
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 16:10 GMT
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Stitches perfect with just min 1.23 and max 2.8 at first optimzing.
How do you crop it.
My guess is that you use circular crop and do not adjust default settings.
You should use fullframe and set the initial lens setting to 10mm.
The problem you have in the grass is because of bad optimizing. Its actually small stitching errors ad in areas like grass or similar i generates smearing.
Hans
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 16:35 GMT
updated: 26 Jun 2012 at 16:57 GMT
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Very Good stitch for first pano, after deleting worst control points (more then 6 distance) and without adding any manual control points. I came to following results;
Average cp distance: 0.77
minimum cp distanxe: 0.03
maximum cp distance: 6.38
Probably can be even better when removing max distance control points and/or adding some manual..
PTgui determined automatic lens parameters "Circular Fisheye" and HFOV 143.7 from the images and no crop was used.
PTgui project file and example .mov are here;
www.virtualvisitbali.com/temp/pano_stitched.zip
The problem you have in the grass of the second pano is not ghosting but also due to misalignment of the images.
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Flashificator
Posts: 136
Location: Lima, Peru
Registered: 16 May 2012
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 16:40 GMT
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If you use the Smartblend plugin for PTGui, you should be able to avoid the smeared seams in grass, carpets, gravel, sand and other similar surfaces.
Trausti
____________________________
Flashificator - User examples
flashificator.com/gallery.htm
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 16:55 GMT
updated: 26 Jun 2012 at 17:00 GMT
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Flashificator said: If you use the Smartblend plugin for PTGui..
Smartblend is, as far as I know, only available for windows though 
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John Houghton
Posts: 3728
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 17:34 GMT
updated: 26 Jun 2012 at 17:35 GMT
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The problem with the 2nd set of images is that the zenith image is UPSIDE DOWN. You can see that just by looking at them and imagining how the images were shot. But you can also check the orientation parameter in the exif data (via the metadata display in Bridge), which confirms that this is so. The camera's orientation sensor gives unreliable data when the camera points vertically up (or down). This matters because the lens shift parameters are being applied inconsistently in the opposite direction to the rest of the images - resulting in poor optimization. With the image the right way up, I got a perfect stitch without any ghosting - so no need of Smartblend!
John
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hindenhaag
Posts: 849
Location: Netherlands
Registered: 7 Mar 2010
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 17:55 GMT
updated: 26 Jun 2012 at 17:58 GMT
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Hi,
I tested D200 on NN5 and the LRS should be around 60mm, not 63mm. I use a 10cm diameter hard paper card with a 8mm center cut out placed below the rotator to test my LRS settings with the method created by Smooth:
www.easypano.com/forum/display_topic_threads.asp?...
Place the camera to panohead, pitch down to 10 - 15º to get the corner of the card, f max, focus to the corner, take your shots around, import to PTGui, output file.mov, move down to nadir, and check the circle of the card. This should be round. In case you see "teeth" cutting to the right, you have to move the LRS to the right. In case it cuts to the left, move to the left. Optimum setting is for example: Setting is 60mm, no tooth, move to 61mm, the tooth should cut to the left, 59 should cut to the right, you should move one mm to the right. Try till you get a set of three: cut to the right, no tooth, cutting to the left. That is the right setting.
Check your URS with www.johnhpanos.com/epcalib.htm.
URS and LRS are the basic for good stitching.
Point two: You get a lot of CA = Chromatic Aberration with the Samyang lens. I checked your pics and stitched them, checked control points being set by PTGui, changed to 100%, you will see a lot of green or purple borders around for example windows. You have to correct this in Raw for example. Otherwise neither PTGui nor you can place correct CP = Control points.
Point three: your pics are not very sharp. Just open up Controlpoints in PTGui in zenith. The margins are not very sharp. Shoot F8 or F11, set focus 1m and tape it. This is the best for Samyang 8mm, in PTGui you have to set it to 9mm because of optical construction of the lens.
I will test D200 NN5 Samyang 8mm for you this week and let you know about my settings.
Sorry to say, you pano is over- and underexposed which is not easy to find CP for PTGuiPro. This is a very tricky place to take a good Pano. What do we like to see as a customer? Information in the back of the windows, a lot overexposed no information left. Opposite of window views of dark areas in the shop. This is a motor shop. What is the basic goal to see in a pano? The bikes. But these areas are under exposed. Result, bad info about the basics of this shop.
What might be a solution? You learn to shoot bracketing set ups. You have to be able to combine overexposed window pics with more important underexposed pics of the shop itself. This is level A of panos.
This is what I personally feel concerning your pano.
Feel free to ask,
Heinz
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dracula
Posts: 2
Location: Donji Miholjac, Croatia
Registered: 26 Jun 2012
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 19:04 GMT
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@Hans I didn' crop it, i always select fullframe fisheye and 9mm, when i do align it changes my focal legth to 9,0151545 mm and it does that too when i enter 10mm before align. I can't get near similar final result without errors from me.
@Marco W I also can't get near as good result from automatic stitching with automatic settings. Optimized just like you with heavy and lens shift.
Can you tell me exactly what version of ptgui do you use. is it latest 9.1.3 or 9.1 that i use.
Just to make sure my workflow with Automatic settings (leave circular Fisheye) is that i load images, press align images, switch to advanced, go to optimizer, optimize with heavy + lens shift, and delete worst control points.
Very similar results i get with Full Frame Fisheye and 9mm or 10 mm settings. but with errors
Here are saved project so you can see what results i've got
www.fkdm.hr/pano/test_settings.zip
Something strange is happening with my ptgui, tried resetting ptgui settings by deleting Configuration.xml, and still no better stiching result.
Can you tell me in Options -> Control Point Generator ->
i have by default 15 and 2500. I suppose that default settings are good. tried also 40 for the first parameter but no luck...
@hindenhaag For this (pano.zip) i actually tooked them BKTed (three different exposures) so final result will be better, for CA i have raw images and i usually deal with CA.
I actually get best sharpness at 0.4m on f8
Will check my URS and LRS but here i think that it doesn't causing problem because Marco W & Hans got excellent results.
Tnx everyone for helping so far....
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John Houghton
Posts: 3728
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Problem Stitching when using zenith image
Posted: 26 Jun 2012 at 21:18 GMT
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dracula said: i always select fullframe fisheye and 9mm, when i do align it changes my focal legth to 9,0151545 mm and it does that too when i enter 10mm before align.
The 9mm is an approximate starting value which the optimizer is free to vary (or rather the derived fov) in its attempts to align the control points. It is to be expected that it will end up with the same final value when you start with a different focal length. However, it does help the optimizer if you set a value near to the correct (expected) value.
I got a good stitch with this project file:
www.johnhpanos.com/FullFrame-9mm-settings-jh.zip
This was based on your project file, but with the addition of some extra points giving an improved spread (using the "generate control points here" option described in the help screen for the control points tab). I used PTGui Pro 9.1.3.
John
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 2:11 GMT
updated: 27 Jun 2012 at 2:31 GMT
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Using PTgui 9.1.3 Pro also, but I doubt that causes the difference between the projects.
As the initial stitching problem occurred between the first image (shot to the counter) and the zenith, it also helps that in John's project file, the pitch and roll radio buttons of the first image are checked on the optimizer window. You could force a similar result (although less preferred) by enabling view point correction for only the zenith image.
Personally I didn't change the lens settings suggested by PTgui and left the default, which worked out fine for me.
Play a little more with the optimizer options and you will get a perfect stitch 
Looking at the nadir area, you LRS is a bit to the right as Heinz explained. Your sharpness looks ok to me as shown by the slight aliasing effect on vertical lines while rotating. When you shot the images in raw, you could reprocess for shadow detail and reduce CA. There is even enough information in the jpg's to recover considerably better detail inside the shop, outside (blown) highlights however are impossible to recover from these jpg's.
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Hans Nyberg
Posts: 2871
Location: Denmark
Registered: 28 Aug 2005
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 7:58 GMT
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The problem is that you are doing a full optimize which includes the c correction by using the heavy+shift option.
c should never be optimized together with the other corrections at least not if you have as much overlap as you have.
Also the Samyang is a special projection which is not in any way available as a fisheye projection in PTGui. c is correcting the center of the images and the center is very special in Stereographic projections as it has almost same resolution as the periferal areas.
When you connect center to center with controlpoints and optimize all corrections at ones you may get some very weird corrections.
Use advanced and do not check for c .
In reality there are very few lenses that needs correction of c and I never use it for any lenses at least not as a first option.
Hans
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Hans Nyberg
Posts: 2871
Location: Denmark
Registered: 28 Aug 2005
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 9:17 GMT
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After doing some more tests it looks like the problems here comes from optimizing only FOV and b (medium) in first optimizing.
In that cases the full optimize is not able to give you correct shift values.
This may also be because of the special projection.
Hans
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 9:47 GMT
updated: 27 Jun 2012 at 9:51 GMT
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What do you choose then for the other optimization parameters, Hans (do you use h/v shift and optimize pitch and roll of image0)?
I get a "very good" optimization without c checked as you suggested, but without checking horizontal/vertical shift and pitch/roll for the first image, I don't get any better then "good" with an average cp distance of between 4 and 5..
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John Houghton
Posts: 3728
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 9:59 GMT
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Marco W said: ... it also helps that in John's project file, the pitch and roll radio buttons of the first image are checked on the optimizer window.
Pitch and roll checked in no way affects the quality of the optimization/alignment. They were checked because of the addtion of vertical line control points to level the panorama.
John
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Problem Stitching when using zenith image
Posted: 27 Jun 2012 at 10:41 GMT
updated: 27 Jun 2012 at 10:42 GMT
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John Houghton said: Pitch and roll checked in no way affects the quality of the optimization/alignment. They were checked because of the addtion of vertical line control points to level the panorama.
See now your vertical control point for leveling on the picture on the wall of image5 which caused the automatic pitch and roll selection of image0 in your project, John.
Don't intend to contradict you nor Hans (as my knowledge of PTGui is limited compared to both of you), and sorry if I am confusing, but without checking roll and pitch for image0, I don't get a "very good" result and don't get rid of the stitching problem between image0 and zenith.
Checking roll and pitch on image0 however makes the stitching error disappear and gives "very good" result in my case, so it must do something by adjusting image0 then, right?
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