code: def matrix_to_points(matrix, pitch, origin):
      
      indices = np.column_stack(np.nonzero(matrix))
      points = indices_to_points(indices=indices,
                                 pitch=pitch,
                                 origin=origin)
      return points
docs: Convert an (n,m,p) matrix into a set of points for each voxel center.
  
      Parameters
      -----------
      matrix: (n,m,p) bool, voxel matrix
      pitch: float, what pitch was the voxel matrix computed with
      origin: (3,) float, what is the origin of the voxel matrix
  
      Returns
      ----------
      points: (q, 3) list of points