code: def speed_direction_batch(dets, tracks):
      tracks = tracks[..., np.newaxis]
      CX1, CY1 = (dets[:, 0] + dets[:, 2]) / 2.0, (
          dets[:, 1] + dets[:, 3]
      ) / 2.0
      CX2, CY2 = (tracks[:, 0] + tracks[:, 2]) / 2.0, (
          tracks[:, 1] + tracks[:, 3]
      ) / 2.0
      dx = CX1 - CX2
      dy = CY1 - CY2
      norm = np.sqrt(dx**2 + dy**2) + 1e-6
      dx = dx / norm
      dy = dy / norm
      return dy, dx
  
imports: import os
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: speed_direction_batch(dets, tracks) and returns: dy,  dx