Relative trajectory playback from different starting pose

1. Given a trajectory in the global frame, a relative trajectory (H_rela) can be generated as:

H_rela = inv(H_1) * H_i

Since the relative transformation is regard to local frame (first pose in the trajectory). H_rela(1) is Identity

2. For a new starting pose in the global frame H_start, a new trajectory begins at the starting pose is generated as:

H_new = H_start * H_rela

where H_new is in the global frame.