agour
Posts: 8
Location: United Kingdom
Registered: 28 Mar 2012
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PTGUI HDR Problems
Posted: 30 May 2012 at 16:29 GMT
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Hey,
I've been having more difficulties with ptgui, when stitching bracketed photos.
My workflow is like this:
1. Shoot 8 around at 15degrees down tilt, 1 zenith at 60degress.
2. Convert the bracketed exposures (3 for each setting, so 27 in total), into jpegs.
3. Use ptgui to align the images, with 'use bracketed images' selected.
4. I'm using a canon 500d with samyang 8mm, so use smooths settings (full frame fisheye and 9mm focal length).
Now the problems start. I always get a 'not bad' on the optimizer.
I also get a strange 'pinching' effect in the preview window, see:
The resulting panorama always has a few small errors.
The weird part is, that if I do the same process with only 1 set of images (no HDR), the photos stitch fine and don't have this 'pinched' effect. There is also only 1 tiny error, which would be easily fixable..
Any ideas of what the problem is, and how I can increase the quality of my control points?
I'm also using a NN3, and I have correctly setup the 2 rails using the grid method.
Any help much appreciated!
-agour
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John Houghton
Posts: 3722
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: PTGUI HDR Problems
Posted: 30 May 2012 at 17:25 GMT
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Agour, It looks like the lens parameters have been evaluated to unlikely values - very different to the ones evaluated for the single exposure stitch. This is probably due to rogue control points being generated. One easy solution is to simply add the remaining images to the single exposure project and link them to the existing images. (Add and then sort the images on the Source Images tab, and them link them on the Image Parameters tab). No further control points or optimization should be necessary. Go straight to Generate Panorama.
John
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Flashificator
Posts: 136
Location: Lima, Peru
Registered: 16 May 2012
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Re: PTGUI HDR Problems
Posted: 30 May 2012 at 20:22 GMT
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This is exactly the same thing I experienced a few times some years ago when using Olympus C8080 WZ that required 30 images for a full sphere. Lens parameters did not change and I never found a solution to this issue. Even though I have retired the camera in question, I would still be interested in a solution if any is found.
Trausti
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Flashificator - User examples
flashificator.com/gallery.htm
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hindenhaag
Posts: 849
Location: Netherlands
Registered: 7 Mar 2010
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 11:19 GMT
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Hi,
Just one question: why do you shoot 8 shots around? 6 shots around already give you an overlap of 46%. 8 shots will end up with 59% overlap.
Can you send us the original set of pics, for example with we transfer?
Heinz
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Bob Stone
Posts: 359
Location: Rochester, NY, United States
Registered: 20 Oct 2007
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 13:39 GMT
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hindenhaag said: Hi,
Just one question: why do you shoot 8 shots around? 6 shots around already give you an overlap of 46%. 8 shots will end up with 59% overlap.
Can you send us the original set of pics, for example with we transfer?
Heinz
Smooth has demonstrated that you only need 4 shots @ -10° and one zenith @ 60° for a total of only five shots. I imagine you could add a hand held nadir to take care of the tripod..
www.panoguide.com/forums/tipsntricks/7284/
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 14:45 GMT
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Continuing on the excessive overlap, I have ready before that too much overlap can confuse PTGui sometimes (correct me if I am wrong).
59% overlap means basically that 9% of every image occurs on 3 images which could maybe cause the confusion of the stitcher!?
More or less images at same focal length result in similar output resolution, so there is no need to shoot more and probably the max would be as Heinz stated above at 6 around with 46% overlap which can come handy for removing flares etc.
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agour
Posts: 8
Location: United Kingdom
Registered: 28 Mar 2012
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 14:49 GMT
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Thanks for the replies, much appreciated!
John - How do I link the images into the pano? Every time I try to load the additional images, PTGUI states that I need to add control points for the new images. I tried selecting the HDR option, but it doesn't seem to link the images.
hindenhaag - I figured if I used 8 I would have less chance of the project messing up, obviously not! Once the problems are fixed Ill try taking 6 in the future (4 seems a bit risky).
Marco - Would be interesting to see if someone else can confirm this! It's weird that it works with a single bracketed set, and not with a HDR set.
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 16:08 GMT
updated: 31 May 2012 at 16:23 GMT
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Indeed strange that with a single set of images it works, but then there are so many more images in the bracketed sets that potentially can screw up the project.
To link the images in PTGui, click "Advanced" at the right side of the screen, load the images on the "source images" screen and link the images on the "Image Parameter" screen. The first image of a set doesn't have the radio box checked, the additional images have to be linked to the first one in a set (with boxes checked).
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John Houghton
Posts: 3722
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: PTGUI HDR Problems
Posted: 31 May 2012 at 16:51 GMT
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Agour, This is how to add and link the images:
1. Select Advanced mode on the Project Assistant tab.
2. Select the Source Images tab.
3. Click the Add button; browse and select the additional images.
4. Click the Sort button. This should put the images in the correct order. They must appear in an exactly repeating exposure sequence. NB. The images previously aligned with control points must be the first in each bracketed set. The camera's bracketing option usually allows you to choose to output the normal exposure first in the sequence. If the order is not like this, move the normal exposure images (i.e. the ones previously aligned) up the list with the move button so that they head each set of images to which they belong.
5. Select the Exposure/HDR tab and enable HDR stitching.
6. To link the images, select the Image Parameters tab.
7. Click on Link HDR. The linked images will now acquire the y,p,r settings from the first image in each set, and will thus be aligned exactly with them.
If you cannot select HDR mode, check the exposure sequences on the Image Parameters tab. They should repeat like 1/100, 1/50, 1/200, 1/100, 1/50, 1/200, 1/100, 1/50, 1/200, .... all shot at the same aperture setting. The order must be the same in each and every set, but within the sets the order can be as you like. It's only important that the already aligned images head each set. No more control points are needed and no further optimization is needed. Ignore any messages to the contrary from PTGui.
John
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Birder
Posts: 73
Location: Boston, United Kingdom
Registered: 1 Apr 2012
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Re: PTGUI HDR Problems
Posted: 1 Jun 2012 at 9:25 GMT
updated: 1 Jun 2012 at 9:28 GMT
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I have a similar setup to you Agour and use almost the same workflow as John describes.
My Workflow is (Images)
1. Set Canon 7d, Samyang 8mm, Manual mode, F8 or F11 focus at .9mtr
2. Test shot to get correct exposure.
3. Set AEB to braketed +2 and -2,
4. Set 7d to 2 second delay so each shutter press automatically takes 3 the images.
5. Shoot 4 around at 12degrees down tilt, 1 zenith at 75degrees up.
6 Download images to PC.
On PC:
1. In ptgui, select the correctly exposed images only,
2. Set ptgui to "Smooths 9mm settings". I have saved in lens database, Project Assistant > Advanced > Lens Settings > Lens Database > Samyang 8mm
3. Project Assistant > Align Images > Then do all the normal control point stuff, optimizing, leveling Etc
(This must be done before adding the other images in you HDR set)
4. Save project
5. Project Assistant > Source Images > Add > Browse and select the +2 -2 additional images.
6. Click Sort button and put the images in the correct order ( 0 +2 -2)
7. Project Assistant > Exposure/HDR tab > Tick Checkbox Enable HDR stitching.
8. The line below Enable HDR stitching should have a html link to "link the images", select this.
9 IF NOT Project Assistant > Image Parameters > Link HDR.
10. Project Assistant > Create Panorama
11. Go for a Coffee.
I have tried making the HDR images in other programs but find this method using PTGui produces the best results
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agour
Posts: 8
Location: United Kingdom
Registered: 28 Mar 2012
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Re: PTGUI HDR Problems
Posted: 20 Jun 2012 at 14:37 GMT
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very delayed reply, but thanks for all the reponses!
Adding the first set of images then linking in the HDR ones works perfectly 
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