Why don't use ba to optimize the shot pose in the resect function?

[lmz-whu]

If using pnp to recover shot pose, in fact, only tracks, which tracks length are more than 3, are used. And it ignores the relation between match pairs not reconstructed.

[YanNoun]

Hi @lmz-whu,

Indeed, the process of adding a new camera is the following https://github.com/mapillary/OpenSfM/blob/main/opensfm/reconstruction.py#L1239-L1268 : 1 - Resect a new shot with PnP 2 - Bundle adjust new added shot with tracks of length >= 3 3 - Triangulate new points (i.e. length == 2) (4 - optionaly, bundle locally or the entire scene)

You're right that newly triangulated points aren't optimal reprojection-wise. We expect this to be fixed in further local/global bundles.

Let me know if that answer your question.

Yann