Sub/Super-script mismatch in pose_measurement.h?

[versatran01]

In
https://github.com/ethz-asl/ethzasl_msf/blob/master/msf_updates/include/msf_updates/pose_sensor_handler/pose_measurement.h

line 313 when you calculate q_err:

q_err = (state.Get<StateQwvIdx>()
          * state.Get<StateDefinition_T::q>()
          * state.Get<StateQicIdx>()).conjugate() * z_q_;

This looks like you are doing (q_wv * q_wi * q_ic)^-1 * z_q_vc, but should it be (q_vw * q_wi * q_ic)^-1 * z_q_vc?

[v0n0]

I looked multiple times at your two formulas, but they look exactly the same?

[versatran01]

@v0n0 the first quaternion is questionable.
In their code it is q_wv that represents a rotation from vision to world, the one I put is q_vw, which represents the opposite rotation.

[v0n0]

Oh yeah, just saw that. These indexes are quite confusing, c = camera is used, then v = visual is used for another, aren't they the same thing? If the variable names were written fully like quaternion_world_to_vision, it would be much simpler and more readable and there would be less errors like this.

[versatran01]

Yes I agree that they are confusing, but more importantly, this code might be wrong.
q_wv * q_wi is meaningless, while q_vw * q_wi gives you q_vi.
Just curious how they get it to work with a wrong expression.

[simonlynen]

Please look at #116

[versatran01]

@simonlynen Thanks.

So this is fixed in that branch but not the master one?