Tweaking Panos in Photoshop

This is actually a question, not a tutorial. In any case I’ll integrate the answers I eventually get to the text, so scroll down if you’re interested (sometimes comments are not indexed by google and I’ll also spread the question in other medias).

Photoshop has a great tool for stitching photos together and them making panoramic (panos), as long as you have overlapped them about 20% and … but sometimes you have to tweak them and that’s when the problem starts.

To explain the problem I’m having, I’ll take the opportunity to show a bit of what photoshop is doing.

Example: small pano in Venice, Italy. Three shots put together and to make my case visually clear I have exaggerated the tone difference between them. Left is 1.5 stop darker and very low saturation, middle is “normal” and right is 1.5 brighter and high saturation.

Photoshop will blend them together light this

Pano of Venice with three shots and exaggerated exposures and saturations.

Pano of Venice with three shots and exaggerated exposures and saturations.

It will use parts of the images and mask the rest, as we can see here.

Masks made by photoshop to stitch the shots together.

Masks made by photoshop to stitch the shots together.

If you notice the sky you’ll see that the plane track in the sky doesn’t really match.

Sky problem from stitching photos together.

Sky problem from stitching photos together.

So the option is to get the whole track from the same shot. And the way to do it is to hide and show in the respective masks. The problem is that photoshop is applying a color match only to what is visible through the masks.

If you deactivate the masks that’s what you have.

Sky problem from stitching photos together. Masks deactivated and color difference.

Sky problem from stitching photos together. Masks deactivated and color difference.

And when you try to bring the hidden part back the colors really don’t match.

Sky problem from stitching photos together. Sky color difference when tweaking the masks to solve stitching problem.

Sky problem from stitching photos together. Sky color difference when tweaking the masks to solve stitching problem.

The question here is what is to be done in this case??? Auto-blend will not help, it will basically rebuild the masks as they were in the first time!!

Another example is here, the missing part of the boat and the canoe that I want gone from my nice Venetian pan (canoes and Venice … really?) and if I just play with the masks, colors might not match properly.

Unwanted or missing parts of the pano.

Unwanted or missing parts of the pano.

Problem with color while removing or bringing back parts of the pano.

Problem with color while removing or bringing back parts of the pano.

One option is cloning luminosity, color, the whole thing, patching it content aware … in some situations it works, but in some others, I already have the proper content, all it’s needed is to repeat the color matching that was applied before.

If you know the answer! Please, let me know!

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About Cris Da Rocha

Astrophysicist, DB manager, cyclist, musician and, why not, "photographer to be". Back to enjoy photography after many years ... it's cool. Might share something nice and get something new.
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7 Responses to Tweaking Panos in Photoshop

  1. Remco says:

    Hi Chris,

    Simple solution: match the photos’ colours before stitching! If you don’t want to do that by hand, or if you can’t get close enough, you could try one of the stitching tools based on the panotools library. They will colour match all photos first and then do the stitching. Hugin is one such program, and open source, too.
    Note that these programs allow much more control than Photoshop offers, which means you can get better results, but you’ll have to do more of the work (selecting matching points in the images, etc.).

    Cheers,
    Remco

    • Remco says:

      P.S. Cris, not Chris! 🙂

    • Hi Remco!

      Starting with color matched images surely does the trick.

      I’ll check Hugin. Photoshop itself has a “match color” thingy but it’s kind of manual, and when you’re stitching 10 shots or so, it is really too much.

      I still don’t understand why photoshop doesn’t extend the color matching “profile” to the masked areas so the transitions are smoother. Sometimes that’s all you need.

      Thanks a lot! 🙂

  2. Remco says:

    Another thing I did when stitching panos was to take the masks that panotools/Photoshop create and to make them softer and more gradual, so any colour differences between overlapping images becomes less noticeable. Think cross-fading two takes in audio recording. Also helps hide misalignments in things like water, sky, grass, …

    • “Mask cross-fading” sounds interesting. I sometimes have to tweak the masks to prevent a “crack” between image. Though sometimes is just a visual thing that is visible in some zoom rates only …

      I’ll give it a try!

  3. Franz says:

    Hey CHris, just for curiosity – could you try stitching the same phots using Microsoft ICE ( http://research.microsoft.com/en-us/um/redmond/groups/ivm/ice/ ) and show the results?
    I hade quite some times where ICE produced better results than PS. Sure, the cut boat will not be removed 😉

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