INS/GPS offset

[Seb_B]

Hello,

I have images coming from a "PPK" drone and other from a "normal accuracy" drone.

In the camera calibration tool. I enable "Adjust GPS/INS offset" for the PPK images. After the alignment and optimize step, I checked the camera calibration window and I see that the group of images with "Adjust GPS/INS offset" enabled do not have any lens adjustement (cx, cy, k, ...) whereas there are camera lens adjustments for the other groups of images (wihtout PPK and "adjsut GPS/INS offset enabled)!

What I need to do for having both "Adjust GPS/INS offset" AND camera lens calibration?

Regards,

Seb

[Alexey Pasumansky]

Hello Seb,

Are you using adaptive camera model fitting option for alignment/optimization operations? Which parameters are selected for the optimize cameras step?

[Seb_B]

Hello Alexey,

I did not use adaptative camera model fitting to have these results.

Actually, what does it mean "adaptative camera modeling"? Does it change the lens model to each image? Not clear to me.
If I use it, will I have a lens model for the group of images with the offset enabled?

Regards,
Seb

[Seb_B]

OK, I found the information for adaptative modeling:
"Adaptive camera model fitting
This option enables automatic selection of camera parameters to be included into adjustment based on their reliability estimates. For data sets with strong camera geometry, like images of a building taken from all the sides around, including different levels, it helps to adjust more parameters during initial camera alignment. For data sets with weak camera geometry , like a typical aerial data set, it helps to prevent divergence of some parameters. For example, estimation of radial distortion parameters for data sets with only small central parts covered by the object is very unreliable. When the option is unchecked, Metashape will refine only the fixed set of parameters: focal length, principal point position, three radial distortion coefficients (K1, K2, K3) and two tangential distortion coefficients (P1, P2)."

Nevertheless, this does not explain the issue. I just tried with adaptative camera modeling and I still don't have any adjusted values.

I tried with enabling also the "enable reference", beside on the left of "Adjust GPS/INS offset" and I have now adjsued values, but the spare point cloud is worse.... I'm digging into the complex behavior of sfm...

[Alexey Pasumansky]

Hello Seb,

If you enable adaptive camera model fitting option, it would mean that Metashape will try to define automatically, which parameters of the interior orientation should be adjusted.

And if you disable this option, then during the alignment F, Cx, Cy, K1, K2, K3, P1 and P2 will be adjusted. While for optimization you have to choose manually, which parameters should be adjusted.