Proper workflow to solve misaligned cameras?


I have a model consisting of 1906 cameras. When I look at the model from the side and watch the position of the camera’s I can see that four of them are misaligned, because their position is below the surface of the earth, so I couldn’t have made the pictures from there:


This image shows the matches between two properly aligned images (top two) and three misaligned images (bottom three):


What is the proper workflow to solve this?



Hi Steven,

did you group your images by exif?
That can sort out initial misalignments like that.
It might be necessary that you delete all components first though (but in a new project of course).

Hi, no i set “camera priors” to “disable” if you mean that.
I tried it as well with “enable” but to no resolve.
Any other suggestions on how to solve this?

I’ve never worked with the camera priors setting before.
What I meant is to group the images by exif on import, that means for each camera / focal length there is a different group which will use the same distortion values. As a result, there should be no erroneous distortion/localisation if the tie points are not ideal on some images, like it seems to be the case with your troublemakers.
You can also do that manually after import - just go to 1D view and select all images with the same focal length and camera, then set the values Calibration Group and Lens Group to something other than -1 (which is standard and means calculate the distortion for each image individually), usually the values are both the same.
It may be neccessary to delete all components before it works because RC might hold onto the false ones if the component is still present. Then you can ungroup them again when you are certain that all are in the right place and run another alignment, which will usually increase the accuracy…

Hi, I’ve used a zoom lens to take these images, with different zoom levels.
So the images are taken with the same lens, but with a different focal length.
I can see this different focal length in the “focal length” field under “prior calibration”, some are 85mm, others 135mm (see the attchment).


So would assigning them to one calibration group make matters worse?

Yes, if you stuff all of them in the same group it is very bad! :slight_smile:

But the idea is to use one group for each focal length.
Best practice for Photogrammetry is to use a fixed lens.
I don’t do that myself, I use zoom as well.
But then you should restrict your zoom steps to a minimum, ideally beginning and end.
I don’t do that myself, but one of my cameras supports zoom steps and with the other I make sure that I take as many images as possible with an intermediate focal length. You definitaly need at least a handful with the same setting, the more, the better. And the fewer you have, the more important it is to put them all into a group.
So click on Images and select all the ones with the same length (ctrl lmb) and set the first one to 1, the second to 2 etc.
Then realign.
Or just create a new project and set Group by Exif (or similar) to True before you drag the images in.

Ok lots of thanks for your help, this did the trick!

Glad it worked!