Re-use cameras between scans - 1 photogroup per camera - for best scale accuracy

[mtbouchard]

Hi,

I have a 48 camera rigid rig of Sony Alpha 7iii's.

I am have a special calibration capture (with a scale bar) which is solved/constrained, and then I want to re-use this exact calibration in subsequent captures for a while.

For a long time I have used the single Photogroup, but I believe the quality should be higher if I split them into 1 camera/group instances so the intrinsics are unique. This has worked but I have found the bundle adjustment(optimize cameras) to slightly change the accuracy of the scale.

I have used code from Alexy to create per sensor groups, and it worked great! I export the xml as a single file.

But..I am having trouble reloading. I had been simply importing the camera, but that doesnt seem to work.

Any help in taking a single calibration.xml and using that to import that instrinsic/extrinsics? I am wondering what parameters to use in optimize camera such that I keep the instrinsics locked, but allow for very minor camera movement.

Thank you!

Matt

[mtbouchard]

Just a slight bump here since I posted near the holiday break.

I have an additional question: can optimize_cameras() be run but only to change their slight position/rotation change? Or is it best done by using "fixed" on the sensor itself (which I now have 1 per camera, since the are all unique). And if so: what is the python call?

Basically I want: to calibrate 1 time per week, re-use the calibration/per cam, but allow for tiny drift from gravity.

Thank you!

Matt Bouchard

[Alexey Pasumansky]

Hello Matt,

If you would like to re-use exterior and interior orientation parameters from one project in another and use Export Cameras / Import Cameras operations, the camera labels in both projects should be the same.

As for the optimization, if you do not want to have the interior orientation parameters to be modified, I would suggest to make sure that all the calibration coefficients are fixed, whereas the values from the reference project are loaded to Initial tab  (sensor.user_calib).

[mtbouchard]

Thanks Alexy.

Quick follow up: what would the python code be to do this? And if all intrinsics are fixed, are the extrinsics optimized during this?

Thanks!

Matt Bouchard