Cause for "BAD LOOP!!!" loop-closing error with visual-inertial input

[makintuo]

Hi,

after switching to using stereo-inertial data with ORB SLAM3 I occasionally get the error "BAD LOOP!!!" when detecting loops in some datasets. In LoopClosing.cc the conditions for this NOT to happen is as follows : if (fabs(phi(0))<0.008f && fabs(phi(1))<0.008f && fabs(phi(2))<0.349f) with phi being : Eigen::Vector3d phi = LogSO3(g2oSww_new.rotation().toRotationMatrix());

Can somebody explain why these values (0.008, 0.008 and 0.349) and what do the values for phi exactly represent? Are the values affected for example by modifying the parameter settings?

In my datasets loop-closing thankfully usually works, but with some datasets I get values such as 0.025053601063417467, -0.010552526522936551 and 0.014575305769087592, being larger than the values mentioned above and causing the bad loop error.