Lightroom: Using Photomerge to make rectified elevations

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I have landed the job of producing a large number of stitched photos of the internal walls of a fire damaged building, approx 100 walls in all. The images have been captured by drone and I am experimenting with automatic stitching in LR and PS. The goal is to produce rectified images that can be used by structural engineers to assess the condition of the masonry and brickwork. Neither PS or LR is producing perfect results and each has different strengths and weaknesses but one thing that seems to trip both up is the doorways and other openings in the walls. The attached screen grabs show a representative selection of captures and the panos produced from them. I guessed that it was the doorway that was causing the problem so I opened the files in PS and roughly filled it with gray. The masked set produced a good result whilst the set from the unedited set is chaotic. These test sets are jpgs but my preference would be to work with the original RAW captures as far as possible.

So to specific questions:

Is it possible to mask or fill in an area of a raw file in LR in this way?

It would be desirable to be able to trace back to the original capture from any given point on the stitch. This is easy in PS because it preserves each source image as a layer. Is there any way to achive the same thing in LR?

Can anyone explain a bit about what the DNG produced by LR's merge acually is? Is it really raw data? Is each pixel from a single source image or are they composite?

Thanks,

William.
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William Chitham

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Posted 7 months ago

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Johan Elzenga, Champion

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Lightroom cannot clone into an empty area, but as you can see in your screenshot, the Panorama Merge dialog has a "Fill Edges" option. That does what you are asking for: it fills the empty edges. You can also stretch the edges with the boundary warp slider. A combination of the two is also possible. Don't expect miracles, however. It might do a reasonable job in your first screenshot, it will fail in the second one because the area that needs filling is way too large.

The panorama DNG is not really a raw file anymore. it's linear RGB in a DNG wrapper.
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William Chitham

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Thanks Johan, I'm not really bothered about the edges surrounding the pano, this is only a small segment of a much larger project, anyway I definitely don't want to use any warping as I'm trying to maintain accurate geometry as far as possible. The problem is that the images that include doorways with views through to distant detail seem to cause the stitch to go wrong as in the second screen grab. With the doorway filled in gray on the source images the merge is much better so my question was how to "fill in" those doorways on a raw file. I have now discovered that making the opening black with an extreme adjustment brush does the trick if I merge in PS though it doesn't help if I merge in LR because the LR merge disregards all adjustments.

I am leaning towards editing the source files in LR then merging in PS now because of this issue aw well as the advantage of having the images as separate layers in PS.
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Yves Crausaz

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Bonjour, désolé, texte original en français puis Google traduira....

Si je comprend bien les prises de vue ont été faites de Haut vers le bas, par colonne, et les colonnes de gauche à droite.

Essayer de fusionner les images format la colonne 1, puis la 2, puis la 3 etc.
Ensuite vous fusionnerez les fichiers résultants.

Car comme les briques formant le mur ne sont pas facilement différentiées d'une image à la suivante, le logiciel à de la difficulté à les assembler.

Si ça ne fonctionne pas essayer aussi par bande horizontale.

Comme ce sont des images prises par un drone, elles ont donc été prises par un déplacement du drone, mais l'objectif est resté à la même distanece et perpenduquilairement au mur.

Donc dans le dialogue de la fusion Panorama, utiliser l'optiom Cylindrical ou l'option perspective et seulement lors de la fusion des bandes cocher Fill Edges.


Hello, grieved, original text in French then Google will translate....

If I understand shots definitely were made of Top downwards, by column, and columns from the left to the right.

Try to merge pictures format the column 1, then 2, then 3 etc.
Then you will merge the resultant files.

Because as the slick up forming the wall are not easily différentiées by a picture in the following, the software in the difficulty in putting together them.

If this does not work try also by horizontal band.

As these are pictures taken by a drone, they were therefore taken by a displacement of the drone, but objective stayed in the same distanece and perpenduquilairement in the wall.

Therefore in the dialogue of fusion Panorama, to use the optiom Cylindrical or perspective option and only during the fusion of bands coachman Fill Edges.

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William Chitham

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Yves, you are correct about the sequence of shots but I find if I merge single columns the geometry is very distorted (an entire column consists of up to 20 shots). Also I am trying to work quickly so the bigger the area I can stitch in one go the better. Photomerge seems to match the pattern of bricks really well but just seems to trip up on these doorways. I think it is "distracted" by the detail in the distance far beyond the plane of the wall I am interested in. Perspective definitely gives the best results as Cylindrical creates horizontal curved lines. If I merge in PS the "Geometric Distortion Correction" seems to help as well.

Thanks, William.
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Yves Crausaz

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William, alors, il y a peut-être trop d'images, elles se superposent trop, si je ne regarde que la porte, j’essaierais d'en supprimer quelques-unes.

Sinon, est-ce que PH ou LR sont les bons logiciels pour traiter des panoramas formés de plusieurs images prises par drones ? SI on vois les propositions c'est principalement pour des panoramas pris avec une camera sur un trépied !

William, then, there are perhaps too much pictures, they overlap too much, if I look only at the door, I would try to abolish someone.

Otherwise, are PS or LR good softwares to treat formed panoramas of several pictures taken by drones? If one see proposals it is in most cases for panoramas taken with one will dope on a tripod!

(Edited)
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William Chitham

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Thanks for the help guys, I'm making progress. I'm having some success now editing and selecting in LR then sending to PS for photomerge. This image is made from about 72 captures and went together easily but I still find that walls with large openings trip up the stitch unless I black out the openings first in LR. It is also a shame there is no control over the geometry at the merge stage. They invariably come out with quite a lot of perspective distortion and there is a cost in image quality to square them up. I'm delivering the final images at a resolution of 1 pix/mm at life size, this one is around 11275 x 18850pix.
William.