How can I stitch a panorama correctly if I moved the camera along the horizontal axis?

Question

Here in Argentina, we have a very fancy street called "Lanin". All the houses and walls on that street have some kind of mosaic stuck to it, and it's very cool. It was made by a local artist who lives on that street.

Because to this piece of urban art is two blocks long, I've decided to make a panorama of it, by moving myself on an horizontal axis while taking photos. I mean, I took one photo, walked one step deeper along the street, took another photo, and so on.

When I tried to stitch it in AutoPano, the following deformed thing came out:

(High res here)

And the other side of the block:

(High res here)

After this, I've learned about parallax error and why you have to avoid moving when making panoramas. I mean, there are a lot of connection errors on both images. Especially in the second one, the part with the corner is quite problematic to stitch because to as I moved, the perspective of the view changed a lot.

So, is there any way to stitch this kind of panorama correctly? Would this only work on plain walls?

Answer 1

What you are trying to construct is a parallel motion panorama. Its been on my TODO List to do so far a while but I have not done it myself yet.

Microsoft ICE supports this. It is the only software which I know of to do automatic stitching of parallel motion panoramas. You will find that option under 'Camera Motion' below and to the left of the preview window.

Answer 2

When you shoot a panorama by only rotating the camera then you're simulating the effect of a wider field of view lens (even if you use a non-standard projection).

If you move the camera then what you're trying to produce has no equivialent in reality, i.e. its not a 2D projection of a 3D scene like most photographs, it's something else all together! Because of this there's no unambiguous way to put the images together.

However I appreciate that in this situation there's no alternative to moving the camera. What I would do is photograph each building head on, the photograph all the gaps between buildings head on, and then join he images along straight vertical lines. That way the buildings will line up, but you'll still have to do some work blending the road/sky. The result will still look a little weird as what you'll produce won't correspond to any view you'd get in real life.

edit: @mattdm raises a good point I'd overlooked, what you want to do in this situation is simulate an orthographic projection, that is the projection you'd get with a an infinite focal length lens based at infinity. The best way to approximate this would be to take as many photos as possible with little horizontal separation between them, and then stitch them as a series of thin vertical slices.

Answer 3

You can use mosaic mode in Hugin for these types of panos.

You have to be in Expert mode (Interface → Expert), but then in the preview window (GL button), under the Move/Drag tab, Drag Mode can be selected as a Mosaic mode.

If this is set, dragging horizontally and vertically changes the translation parameters X and Y, respectively i.e., lets you move the virtual camera horizontally and vertically.

Answer 4

I'm not sure this is a perfect solution, but I'd give Hugin a try. One of the features I love about Hugin is the ability to define straight lines that extend across photos. This gives the software an extra clue about what should end up looking straight once the panorama is assembled.

I've never tried making a horizontal movement panorama like this, but the thing that sold me on Hugin was a panorama I shot with a lot of buildings and a long dock in a harbor. Everything else I used ended up warping the dock, but in Hugin, I was able to define a line that extended the length of the dock, and this let Hugin produce a very reasonable-looking output.

Answer 5

Canon's PhotoStitch has two stitching modes - Panning and Parallel. It even factors in the focal length your frames were captured with. If you shoot with a Canon, you should have the software in the Canon Utilities disk.

Whatever software you use, however, try shooting with the longest focal length to eliminate geometry distortions. It becomes a tradeoff between the distortion and the number of frames you need to cover your subject.

Additionally, get a leveler and make sure your camera is horizontal when you take the shots, and as much as possible, make its height constant. This will reduce the rotation/translation problems.

Answer 6

Here is one I did by overlapping images that were shot going down the street. This was with photoshop using the measure tool and "Rotate Canvas" Arbitrary to get the verticals straight and parallel. Then the images were cropped, merged and erased the non aligning overlapping parts of the images. It is time consuming and is not the software answer you want, but it works. One thing to be aware of is if there are any things like awnings or signs that are 3d, you need to be sure you have straight on images to use.

http://www.knightvisionphotography.com/FranklinMainStreet.pdf

Answer 7

I suspect the problem is that you are not taking a Panorama. You are simply taking multiple shots that should be simply appended one to the other. I would expand the canvas in Photoshop and simply place each photo one next to the other.

The result will look like a panorama, but will actually simply be a very long photograph.

Answer 8

I would first try and correct your photo for lens distortions using the Lightroom camera profiles.

Then you could try to create a panorama using photoshop which has an option for merging pictures without the usual corrections.

Although normally I would advise anyone to use AutoPano pro, this time it seems Photoshop's attempt at panorama stitching might help.

Answer 9

I have tried several different programs that will merge photos into panoramas. The one that I use most of the time is Photoshop Elements. This is a rather cheap version of Photoshop that has most features, but not all, that Photoshop has.

You can download a 30 day trial och try out the different ways that Photoshop Elements can stitch your photos into a panorama. There is even a manual mode, though I have not tried that one, yet.

Good luck (I'm just a customer of theirs and have no interests in you buying this software)