On 1/27/20 12:36 AM, Doug & Kathy Davies via gimp-user-list wrote:

Good Day,

New here and have a question. I want to create a photo backdrop for my model railway. It is an urban scene and I have taken a series of photos laterally across the potential area. I now need to 'stitch' them together to form a continuous photo I can get printed and use as the backdrop. My question...can I use GIMP to get this done?

Looking forward to hearing from some replies.

The best tool for this is Hugin: http://hugin.sourceforge.net/

On Sun, 2020-01-26 at 15:36 -0800, Doug & Kathy Davies via gimp-user- list wrote:

My
question...can I use GIMP to get this done?

You may find hugin or another panorama stitcher is better at it. Hugin takes a little work to get used to, but can get good results. Then maybe use GIMP to clean up the result.

There are four steps, whichever program you use: (1) combine all the images into one big image, e.g.one per layer (File-

open as layers in gimp)

(2) correct for rotation and make obvious exposure corrections to the photos - this is especially necessary if the lighting, focus, or camera settings such as exposure time and aperture varied between shots at all;
(3) determine known common points in each pair of pictures and move them to connect at these points, using perspective and barrel distort as needed
(4) correct colour casts, darkness etc between separate parts of the joined-up image and crop away the uneven edges.

Hugin will do step 3, which is the hardest part. The others, you can do in gimp.

Liam (slave ankh)

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Doug asks:

I have taken a series of photos
laterally across the potential area. I now need to 'stitch' them together

Liam R E Quin writes:

There are four steps, whichever program you use: (1) combine all the images into one big image, e.g.one per layer (File-

open as layers in gimp)

(2) correct for rotation and make obvious exposure corrections to the photos - this is especially necessary if the lighting, focus, or camera settings such as exposure time and aperture varied between shots at all;
(3) determine known common points in each pair of pictures and move them to connect at these points, using perspective and barrel distort as needed
(4) correct colour casts, darkness etc between separate parts of the joined-up image and crop away the uneven edges.

(5) If the edges still don't match perfectly, use layer masks with black/white gradients to fade out the edges of adjacent images so each image blends into the next.

Hugin will do step 3, which is the hardest part. The others, you can do in gimp.

Hugin can be hard to use and doesn't work on every collection of photos, but when it works, it does an amazing job on steps 3 and 4 both. Definitely try it.

And Doug: when googling for more info on this technique, "panorama" is a helpful search keyword. You should find lots of tutorials and examples if you include that in your search.

...Akkana