Thanks for your answers.
For the question why this shift, I think it is because the calibration during survey somehow went bad, so the calibration was done after the survey (and after transporting the ROV). What’s more, it wasn’t performed with a single stereo camera, but with 2 distinct monocular cameras (with synchronized trigger). So I suspect one camera moved a little bit between the data acquisition and the a-posterior calibration.
The acquisition and calibration wasn’t done by my company but by some partner, so I don’t know the calibration scores.
I will of course use our own data and calibration once we get it, but it won’t be for the next couple of weeks for in-air data, and a few month for submarine data.
So until then, excepted if you know a public submarine stereo dataset, I will have to work with this record, so I would like to correct the bad calibration as good as possible. So if you have an idea how to correct a shift, I’m still interested.
Or maybe an alternative option could be to try to do calibration from the stereo video itself (15 minutes). However there are no chessboards/tags in the record, and features are not the easiest to work with (plants, shells, rocks, … rather than man made geometrical shapes with nice corners)