Question about the information matrix

[Ethan-Zhou]

Hi all, my question is about the information matrix passing to the back-end (pose graph).

In dvo_slam/dvo_core/src/dense_tracking.cpp line 372 and dvo_slam/dvo_slam/src/keyframe_tracker.cpp line 147, there is a magic number 0.008. What is it?

Besides, which parameterization does g2o's function edge->SetInformation() prefer? My understanding is that Christian pass the information matrix of se(3) vector. But in the g2o paper, quarternion is used. I am confused...