rigid_transform.py 文件源码

def skew(v, return_dv=False):
  """ 
  Returns the skew-symmetric matrix of a vector
  Ref: https://github.com/dreamdragon/Solve3Plus1/blob/master/skew3.m

  Also known as the cross-product matrix [v]_x such that 
  the cross product of (v x w) is equivalent to the 
  matrix multiplication of the cross product matrix of 
  v ([v]_x) and w

  In other words: v x w = [v]_x * w
  """
  sk = np.float32([[0, -v[2], v[1]],
                   [v[2], 0, -v[0]],
                   [-v[1], v[0], 0]])

  if return_dv: 
      dV = np.float32([[0, 0, 0], 
                       [0, 0, -1], 
                       [0, 1, 0], 
                       [0, 0, 1], 
                       [0, 0, 0], 
                       [-1, 0, 0], 
                       [0, -1, 0], 
                       [1, 0, 0], 
                       [0, 0, 0]])
      return sk, dV
  else: 
      return sk