code: def polar2cart(r, phi, center):
      
      x = r*np.cos(phi)
      y = r*np.sin(phi)
      return x - center[0], y - center[1]
docs: transforms polar coords [r,phi] into cartesian coords [x,y] in the frame of the lense center
  
      :param coord: set of coordinates
      :type coord: array of size (n,2)
      :param center: rotation point
      :type center: array of size (2)
      :returns:  array of same size with coords [x,y]
      :raises: AttributeError, KeyError