how to fix this panorama alignment problem

[bob_estremera]

<p>So close,<br>

Panorama software really shows their shortcomings when doing even the simplest stitching of interior architecture.<br /> But I'm so frustratingly close with this one little issue.<br>

I've tried PTGui, Hugin and others and this one issue keeps popping up.<br /> The large complete pano looks really nice, 3 images taken on a Panosaurus Rex, dead level, 25% overlap.<br>

The line where walls meet ceiling is always a problem.<br /> I've included a close up.<br>

This was a Photoshop CS3 photomerge. Looks fabulous, to me, except the mismatched crown molding.<br /> I know the clone tool but can't figure out a way to fix. On the closeup, the right side is most obvious but you can see also on the right, a bit of a jog.<br>

Can someone tell me how I can fix these consistently because they will always be a problem.<br>

Thanks, Bob</p><div></div>

[bob_estremera]

<p>And here is the close up.<br /> Bob</p><div></div>

[joe chan]

<p>You could perhaps try correcting the verticals in the three images before trying to stitch them.</p>

[bill_mussett1]

<p>Bob, I use Hugin or for simple panoramas, Calico. I read your first post and my thought then was why use only three images. The more information the stitching program has to work with the better the results; to a point. It looks like PS has primarily used your first and third images and the second as fill. That could explain the location of the mismatches. As to why the mismatches do not run the vertical length of the image, that's something I can't explain. My only suggestion for you is to try taking more than three images; try four or five. I assume your camera is level through-out the rotation and you have determined the nodal point of your lens.</p>

<p>P.S.: Add comments to your original post rather than starting a new post for the same issue. </p>

 

[monika_epsefass]

<p>How do you assemble your panoramas? I've had the same problem with the automated PS CS3 version, when I chose "reposition only" and the pictures weren't exactly level. Your photos must be highly accurate, or you need to chose the first option (don't remember what it's called, and don't have PS at hand at this computer)</p>

[paulh]

<p>Bob<br>

It does take some time and patience to learn how to get the best out of panorama stitching.</p>

<p>Are you 100% sure you have the camera correctly positioned on the panoramic head for this lens - this is important for interior / close quarter panoramas, less so for landscape ones.</p>

<p>With the wide angle lens you are using, you should experiment with more overlap - up to 50% can make life easier. You may find that using a longer lens and more images gives a better result.</p>

<p>I've had good results with Hugin, stitching up to almost 100 images into one landscape panorama. I have tried Autopano Pro, and found that to be excellent, especially with interior and larger panoramas (70+ images).</p>

<p>Finally, if you still can't get it quite right with the stitching software, you can still (usually) fix it in PS. I have found for issues like this that you are better off with layers, selecting the problem areas, and using the transform tools to do the major fixing (I forget the exact methods, it's been a few months since I did it last...), then do minor fixes with the clone stamp.</p>

[bob_estremera]

<p>Sorry about the second post. I couldn't find a way to add 2 images in one post.<br /> My images are accurate, camera was level (using bubble level) and verticals are vertical throughout.<br /> I shot all three on a Panosaurus Rex pano head-nodal point is correct.<br>

Also, the reasoning for the interior panos is that I've tried to capture larger fields of view with wide angle lenses but the distortion is too objectionable and room dimensions appear much larger than they are. Hence my road to using a few images to increase the field of view while controlling distortion.<br>

Regarding shooting more photos, I don't want to extend the length of the pano more than it is.<br /> Are you saying that as long as my left side and right side end frames end about where they do now (in my sample), that more 'interior' images will help with alignment?<br>

Thanks</p>

 

[JeffOwen]

<p>For many years I always did my stitching manually in Photoshop spending many hours getting everything just right. I had tried several programs and non seemed to work very well until I used Panorama Studio. It is not an expensive program and you can try it out for free if you want to see if it solves your problem.</p>

 

If you have the skills the alignment problems you show can be fairly easily sorted but as you say it should be sorted by the panorama software in the first place.

[danny_wong2]

<p>What focal length were you using, try a normal focal length to give you a more straight perspective on your original shots.<br>

Your window directly under the mismatch is distorted - dead giveaway as to where the issue is.</p>

[bruced530]

<p>Hey Bob ,have been doing a few of these myself recently, and running into the same issues. I'm using PTGUI,and with it seems to be control points and having them spread across the right areas. It seems you can have everything perfectly setup and still have the issues. I've had it outside with powerlines and inside with moldings and ceilings.After I spread my control points out it seems to get better, but there always seems to be something that doesn't quite lineup.<br>

What did you use for a lens? Also how many degrees do you think the pano is, 180 degrees maybe?<br>

Do you think you could put up maybe half size originals and let us have a go ?</p>

[bob_estremera]

<p>Hey Bruce,<br>

Yes, I'll try to put up the 3 shots.<br /> The angle of view is not that large really. I'd say around 90 degrees. I was shooting from the opposite corner into the far wall (middle of the scene). Then I shot one shot to the left and one to the right with about a 25% overlap.<br /> I was shooting with a 18-55 lens at the 18mm setting, 28mm equivalent. I can also try to shorten the focal length but then I'll lose a lot of the 'volume' of the room.<br>

At my life-sucking day job now but will post the 3 images when I get home.<br>

Thanks, Bob</p>

[oar]

<p>With hugin you can use control points to align the photos. Consider setting control points where important lines have to match up.</p>

[bob_estremera]

<p>Mike, I've tried Hugin (it was also sooo close to working well), including adding control points.<br /> The problem here is that there is no clear point or intersection along the ceiling line. They are long lines with no breaks. I suppose I could try the corners where the molding meets the lantern and some more around the window frame where right angles converge.<br>

Thanks, Bob</p>

[r_johnston]

<p>Are you shooting with the camera horizontal or vertical?<br>

Ive been shooting panoramas with the camera vertical, and get much better results even on hand-held shots. In PS.CS3 have had good results with landscapes, some have as many as 16-25 images for Yellowstone lake or mountain ranges like the Tetons.<br>

It may be different in a room, but if you have not tried it, it might work.</p>

 

[paulh]

<p>Bob</p>

<p>By shooting more images for the pano, you're not making the final panorama bigger. Typically, to make life easy for close quarter shots, you should be looking for 1/3rd overlap with a standard (50mm-e) lens. For a wider lens, you may want up to 50% overlap. Adding the extra frames takes way less time than trying to fix the errors in the stitched output.</p>

<p>You do need to bear in mind where control points could be created when actually shooting - this is especially important when you have large featureless walls (or sky).</p>

<p>Try it - more shots with your 18mm, then do the same with a longer lens (50mm-e) which will require more frames for the same output view. Then stitch them (I'd recommend autopano pro, trial versions are available) and see which gives the best results. </p>

<p> </p>

[bob_estremera]

<p>I'm going to be doing another shoot in that same space this Friday and will shoot more images at both wide and more narrow focal lengths.<br /> Bruce, I've attached (at least I hope I did) 3 smaller versions of the original.<br>

Keep in mind, I'm not only looking at the alignment of the molding but notice the window on the left side of the image, Hugin aligned the molding nicely but widened that left side window quite a bit. I may just be expecting too much from stitching but improving my capture technique will be the first step.<br>

Thanks all, Bob</p><div></div>

[bob_estremera]

<p>sorry, somebody has to tell me how to upload more than one image at a time.</p><div></div>

[bob_estremera]

<p>sorry, last one, really sorry</p><div></div>

[paulh]

<p>To upload more than one image at a time, you need to host your images somewhere else (here in your PN gallery, on flickr, etc.), then use the insert image button (the one that looks like a tree) to insert each image into the message body.</p>

[User_503771]

<p>Looking at your three photos, it's obvious that your focal length is way too short for this kind of work. Look from one to another and you'll see how the phone changes its appearance, as do the chairs, etc. and so on. Angles change. Ideally you would shoot six or eight photos with a longer focal length that doesn't give perspective distortion towards the edges.</p>

<p>Another thing to consider: To get your shots to line up well, you should never tilt the camera because that changes the geometry.</p>

<p>This is why they make tilt-shift lenses, and especially why people use view cameras for this kind of shot.</p>

 

[JeffOwen]

<p>I took your three shots and put them into Panorama Studio to auto stitch them together. I used the EXIF data to correct for the lens distortions but was not sure I used them correctly set. As such I had to apply a degree of warp control in Photoshop to get the same proportions that you had on your original image.<br>

I think the auto stitching went very well without any of the ghosting lines you reported. Attached is a small crop of the area of concern.</p><div></div>

[JeffOwen]

<p>This is the full size image using Panorama Studio.</p><div></div>

[bob_estremera]

<p>Thanks for all the guidance,<br>

I think the first thing I'm going to try is to shorten the focal length and take 4 images at approx. 50% overlap rather than 3 wide at 25% overlap.<br>

Jeff, thanks for the effort and the results. I still see, to a much lesser degree, that little 'jog' of molding above the left side of the right hand window. Also, the entire crown molding, on the upper edge, is a bit wavy.<br /> But certainly much improved.<br>

Thanks all. I have some more homework to do and will post results and observations.<br>

Bob</p>

[john_houghton]

<p>The images stitch very well in PTGui, though the setup of the panohead could be better: there is very clear parallax visible on the chair in the foreground, as revealed in this crop from a psd layered stitch:<br>

http://www.johnhpanos.com/pano-px.gif<br>

This is the stitch at 2000x1106:<br>

http://www.johnhpanos.com/pano-px.jpg<br>

I also levelled the panorama to get the verticals accurately vertical. 25-30% image overlap should be ample to give a good stitch.</p>