“…Usually, 3D triangulation can be performed using disparity and stereo extrinsic parameters [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. The stereo extrinsic parameters are calibrated offline [ 32 , 33 ] or online [ 34 , 35 , 36 , 37 , 38 , 39 ]. Active vision systems of the first category only need offline calibration as the stereo extrinsic parameters are fixed, since one camera is static with respect to (w.r.t) the other.…”